21020564635 has 32 divisors (see below), whose sum is σ = 29614320000. Its totient is φ = 14317188480.

The previous prime is 21020564627. The next prime is 21020564683. The reversal of 21020564635 is 53646502012.

It is not a de Polignac number, because 21020564635 - 2³ = 21020564627 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21020564635.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 214405 + ... + 296665.

It is an arithmetic number, because the mean of its divisors is an integer number (925447500).

Almost surely, 2^21020564635 is an apocalyptic number.

21020564635 is a deficient number, since it is larger than the sum of its proper divisors (8593755365).

21020564635 is an equidigital number, since it uses as much as digits as its factorization.

21020564635 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 82436 (or 82422 counting only the distinct ones).

The product of its (nonzero) digits is 43200, while the sum is 34.

The spelling of 21020564635 in words is "twenty-one billion, twenty million, five hundred sixty-four thousand, six hundred thirty-five".