21665535552 has 84 divisors (see below), whose sum is σ = 63544612560. Its totient is φ = 7053887232.

The previous prime is 21665535547. The next prime is 21665535559. The reversal of 21665535552 is 25553556612.

21665535552 is a `hidden beast` number, since 2 + 1 + 6 + 65 + 5 + 35 + 552 = 666.

It is a junction number, because it is equal to n+sod(n) for n = 21665535498 and 21665535507.

It is not an unprimeable number, because it can be changed into a prime (21665535559) 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, 412602 + ... + 462137.

Almost surely, 2^21665535552 is an apocalyptic number.

It is an amenable number.

21665535552 is an abundant number, since it is smaller than the sum of its proper divisors (41879077008).

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

21665535552 is a wasteful number, since it uses less digits than its factorization.

21665535552 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 874800 (or 874787 counting only the distinct ones).

The product of its digits is 1350000, while the sum is 45.

The spelling of 21665535552 in words is "twenty-one billion, six hundred sixty-five million, five hundred thirty-five thousand, five hundred fifty-two".