21635604056 has 32 divisors (see below), whose sum is σ = 44350724880. Its totient is φ = 9813014400.

The previous prime is 21635604043. The next prime is 21635604061. The reversal of 21635604056 is 65040653612.

It is a happy number.

It is a super-2 number, since 2×21635604056² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 226091 + ... + 307226.

Almost surely, 2^21635604056 is an apocalyptic number.

It is an amenable number.

21635604056 is an abundant number, since it is smaller than the sum of its proper divisors (22715120824).

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

21635604056 is a wasteful number, since it uses less digits than its factorization.

21635604056 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 533795 (or 533791 counting only the distinct ones).

The product of its (nonzero) digits is 129600, while the sum is 38.

The spelling of 21635604056 in words is "twenty-one billion, six hundred thirty-five million, six hundred four thousand, fifty-six".