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BaseRepresentation
bin10000111011101110…
…00100001110100010
3212110120011000211200
420131313010032202
5122104233042330
64102025422030
7441165311064
oct103567041642
925416130750
109090909090
11394564360a
12191863a916
13b1b55cc63
1462351b734
15383187a60
hex21ddc43a2

9090909090 has 96 divisors (see below), whose sum is σ = 24304879872. Its totient is φ = 2356128000.

The previous prime is 9090909031. The next prime is 9090909127. The reversal of 9090909090 is 909090909.

It is a Harshad number since it is a multiple of its sum of digits (45).

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

9090909090 is an undulating number in base 10.

9090909090 is a modest number, since divided by 909090 gives 9090 as remainder.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 995445 + ... + 1004535.

It is an arithmetic number, because the mean of its divisors is an integer number (253175832).

Almost surely, 29090909090 is an apocalyptic number.

9090909090 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 9090909090, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (12152439936).

9090909090 is an abundant number, since it is smaller than the sum of its proper divisors (15213970782).

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

9090909090 is a wasteful number, since it uses less digits than its factorization.

9090909090 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9416 (or 9413 counting only the distinct ones).

The product of its (nonzero) digits is 59049, while the sum is 45.

The square root of 9090909090 is about 95346.2589197919. The cubic root of 9090909090 is about 2087.0640223537.

9090909090 divided by its sum of digits (45) gives a palindrome (202020202).

Adding to 9090909090 its reverse (909090909), we get a palindrome (9999999999).

The spelling of 9090909090 in words is "nine billion, ninety million, nine hundred nine thousand, ninety".