21527268921 has 12 divisors (see below), whose sum is σ = 31194292948. Its totient is φ = 14305659264.

The previous prime is 21527268911. The next prime is 21527268937. The reversal of 21527268921 is 12986272512.

21527268921 is a `hidden beast` number, since 2 + 1 + 527 + 26 + 89 + 21 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 10938858921 + 10588410000 = 104589^2 + 102900^2 .

It is not a de Polignac number, because 21527268921 - 2¹⁰ = 21527267897 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21527268911) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 3818140 + ... + 3823773.

Almost surely, 2^21527268921 is an apocalyptic number.

It is an amenable number.

21527268921 is a deficient number, since it is larger than the sum of its proper divisors (9667024027).

21527268921 is a wasteful number, since it uses less digits than its factorization.

21527268921 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7642232 (or 7642229 counting only the distinct ones).

The product of its digits is 241920, while the sum is 45.

The spelling of 21527268921 in words is "twenty-one billion, five hundred twenty-seven million, two hundred sixty-eight thousand, nine hundred twenty-one".