21604583520 has 192 divisors, whose sum is σ = 81432872640. Its totient is φ = 5318037504.

The previous prime is 21604583509. The next prime is 21604583549. The reversal of 21604583520 is 2538540612.

21604583520 is a `hidden beast` number, since 2 + 16 + 0 + 45 + 83 + 520 = 666.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 136189 + ... + 248508.

It is an arithmetic number, because the mean of its divisors is an integer number (424129545).

Almost surely, 2^21604583520 is an apocalyptic number.

21604583520 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21604583520 is an abundant number, since it is smaller than the sum of its proper divisors (59828289120).

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

21604583520 is a wasteful number, since it uses less digits than its factorization.

21604583520 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 384734 (or 384720 counting only the distinct ones).

The product of its (nonzero) digits is 57600, while the sum is 36.

The spelling of 21604583520 in words is "twenty-one billion, six hundred four million, five hundred eighty-three thousand, five hundred twenty".