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21431620 = 22572191151
BaseRepresentation
bin101000111000…
…0010101000100
31111022211122201
41101300111010
520441302440
62043204244
7350110600
oct121602504
944284581
1021431620
1111108991
127216684
134594c42
142bbc500
151d3519a
hex1470544

21431620 has 72 divisors (see below), whose sum is σ = 55157760. Its totient is φ = 6955200.

The previous prime is 21431593. The next prime is 21431623. The reversal of 21431620 is 2613412.

It is a Harshad number since it is a multiple of its sum of digits (19).

It is not an unprimeable number, because it can be changed into a prime (21431623) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 18045 + ... + 19195.

It is an arithmetic number, because the mean of its divisors is an integer number (766080).

Almost surely, 221431620 is an apocalyptic number.

21431620 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21431620, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (27578880).

21431620 is an abundant number, since it is smaller than the sum of its proper divisors (33726140).

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

21431620 is a wasteful number, since it uses less digits than its factorization.

21431620 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1193 (or 1184 counting only the distinct ones).

The product of its (nonzero) digits is 288, while the sum is 19.

The square root of 21431620 is about 4629.4297705009. The cubic root of 21431620 is about 277.7697833551.

The spelling of 21431620 in words is "twenty-one million, four hundred thirty-one thousand, six hundred twenty".

Divisors: 1 2 4 5 7 10 14 19 20 28 35 38 49 70 76 95 98 133 140 190 196 245 266 380 490 532 665 931 980 1151 1330 1862 2302 2660 3724 4604 4655 5755 8057 9310 11510 16114 18620 21869 23020 32228 40285 43738 56399 80570 87476 109345 112798 153083 161140 218690 225596 281995 306166 437380 563990 612332 765415 1071581 1127980 1530830 2143162 3061660 4286324 5357905 10715810 21431620