21557797632 has 216 divisors, whose sum is σ = 74775733760. Its totient is φ = 5835110400.

The previous prime is 21557797571. The next prime is 21557797661. The reversal of 21557797632 is 23679775512.

21557797632 is a `hidden beast` number, since 2 + 1 + 5 + 577 + 9 + 7 + 63 + 2 = 666.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 271257 + ... + 341607.

Almost surely, 2^21557797632 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21557797632, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (37387866880).

21557797632 is an abundant number, since it is smaller than the sum of its proper divisors (53217936128).

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

21557797632 is a wasteful number, since it uses less digits than its factorization.

21557797632 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 70399 (or 70382 counting only the distinct ones).

The product of its digits is 5556600, while the sum is 54.

The spelling of 21557797632 in words is "twenty-one billion, five hundred fifty-seven million, seven hundred ninety-seven thousand, six hundred thirty-two".