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909090 = 233571337
BaseRepresentation
bin11011101111100100010
31201012001000
43131330202
5213042330
631252430
710504260
oct3357442
91635030
10909090
11571016
1237a116
1325aa30
14199430
1512e560
hexddf22

909090 has 128 divisors (see below), whose sum is σ = 3064320. Its totient is φ = 186624.

The previous prime is 909089. The next prime is 909091. The reversal of 909090 is 90909.

It is an interprime number because it is at equal distance from previous prime (909089) and next prime (909091).

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a super Niven number, because it is divisible the sum of any subset of its (nonzero) digits.

It is an alternating number because its digits alternate between odd and even.

909090 is an undulating number in base 10.

909090 is a modest number, since divided by 9090 gives 90 as remainder.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (909091) by changing a digit.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 24552 + ... + 24588.

It is an arithmetic number, because the mean of its divisors is an integer number (23940).

2909090 is an apocalyptic number.

909090 is a gapful number since it is divisible by the number (90) formed by its first and last digit.

It is a practical number, because each smaller number is the sum of distinct divisors of 909090, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1532160).

909090 is an abundant number, since it is smaller than the sum of its proper divisors (2155230).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

909090 is a wasteful number, since it uses less digits than its factorization.

909090 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 73 (or 67 counting only the distinct ones).

The product of its (nonzero) digits is 729, while the sum is 27.

The square root of 909090 is about 953.4621125142. The cubic root of 909090 is about 96.8728983242.

909090 divided by its sum of digits (27) gives a triangular number (33670 = T259).

Adding to 909090 its reverse (90909), we get a palindrome (999999).

It can be divided in two parts, 9090 and 90, that added together give a triangular number (9180 = T135).

The spelling of 909090 in words is "nine hundred nine thousand, ninety".

Divisors: 1 2 3 5 6 7 9 10 13 14 15 18 21 26 27 30 35 37 39 42 45 54 63 65 70 74 78 90 91 105 111 117 126 130 135 182 185 189 195 210 222 234 259 270 273 315 333 351 370 378 390 455 481 518 546 555 585 630 666 702 777 819 910 945 962 999 1110 1170 1295 1365 1443 1554 1638 1665 1755 1890 1998 2331 2405 2457 2590 2730 2886 3330 3367 3510 3885 4095 4329 4662 4810 4914 4995 6734 6993 7215 7770 8190 8658 9990 10101 11655 12285 12987 13986 14430 16835 20202 21645 23310 24570 25974 30303 33670 34965 43290 50505 60606 64935 69930 90909 101010 129870 151515 181818 303030 454545 909090