21513996136 has 8 divisors (see below), whose sum is σ = 40338742770. Its totient is φ = 10756998064.

The previous prime is 21513996109. The next prime is 21513996139. The reversal of 21513996136 is 63169931512.

It can be written as a sum of positive squares in only one way, i.e., 18953028900 + 2560967236 = 137670^2 + 50606^2 .

It is a tau number, because it is divible by the number of its divisors (8).

It is not an unprimeable number, because it can be changed into a prime (21513996139) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1344624751 + ... + 1344624766.

Almost surely, 2^21513996136 is an apocalyptic number.

It is an amenable number.

21513996136 is a deficient number, since it is larger than the sum of its proper divisors (18824746634).

21513996136 is a wasteful number, since it uses less digits than its factorization.

21513996136 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2689249523 (or 2689249519 counting only the distinct ones).

The product of its digits is 262440, while the sum is 46.

The spelling of 21513996136 in words is "twenty-one billion, five hundred thirteen million, nine hundred ninety-six thousand, one hundred thirty-six".