21657133556 has 12 divisors (see below), whose sum is σ = 37957325700. Its totient is φ = 10812183360.

The previous prime is 21657133517. The next prime is 21657133601. The reversal of 21657133556 is 65533175612.

It can be written as a sum of positive squares in 2 ways, for example, as 20083424656 + 1573708900 = 141716^2 + 39670^2 .

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 4092881 + ... + 4098168.

It is an arithmetic number, because the mean of its divisors is an integer number (3163110475).

Almost surely, 2^21657133556 is an apocalyptic number.

It is an amenable number.

21657133556 is a deficient number, since it is larger than the sum of its proper divisors (16300192144).

21657133556 is a wasteful number, since it uses less digits than its factorization.

21657133556 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8191714 (or 8191712 counting only the distinct ones).

The product of its digits is 567000, while the sum is 44.

The spelling of 21657133556 in words is "twenty-one billion, six hundred fifty-seven million, one hundred thirty-three thousand, five hundred fifty-six".