21657236552 has 32 divisors (see below), whose sum is σ = 47487633600. Its totient is φ = 9065818944.

The previous prime is 21657236551. The next prime is 21657236617. The reversal of 21657236552 is 25563275612.

It is not an unprimeable number, because it can be changed into a prime (21657236551) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 4494527 + ... + 4499342.

It is an arithmetic number, because the mean of its divisors is an integer number (1483988550).

Almost surely, 2^21657236552 is an apocalyptic number.

It is an amenable number.

21657236552 is an abundant number, since it is smaller than the sum of its proper divisors (25830397048).

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

21657236552 is a wasteful number, since it uses less digits than its factorization.

21657236552 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8993925 (or 8993921 counting only the distinct ones).

The product of its digits is 756000, while the sum is 44.

The spelling of 21657236552 in words is "twenty-one billion, six hundred fifty-seven million, two hundred thirty-six thousand, five hundred fifty-two".