21565657036 has 48 divisors (see below), whose sum is σ = 48570181632. Its totient is φ = 8131161600.

The previous prime is 21565656977. The next prime is 21565657073. The reversal of 21565657036 is 63075656512.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1119781 + ... + 1138876.

It is an arithmetic number, because the mean of its divisors is an integer number (1011878784).

Almost surely, 2^21565657036 is an apocalyptic number.

It is an amenable number.

21565657036 is an abundant number, since it is smaller than the sum of its proper divisors (27004524596).

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

21565657036 is a wasteful number, since it uses less digits than its factorization.

21565657036 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2258710 (or 2258708 counting only the distinct ones).

The product of its (nonzero) digits is 1134000, while the sum is 46.

The spelling of 21565657036 in words is "twenty-one billion, five hundred sixty-five million, six hundred fifty-seven thousand, thirty-six".