21566685507572 has 12 divisors (see below), whose sum is σ = 37757780481120. Its totient is φ = 10778748227256.

The previous prime is 21566685507569. The next prime is 21566685507617. The reversal of 21566685507572 is 27570558666512.

It is a happy number.

It is a super-2 number, since 2×21566685507572² (a number of 27 digits) contains 22 as substring.

It is a hoax number, since the sum of its digits (65) coincides with the sum of the digits of its distinct prime factors.

It is a junction number, because it is equal to n+sod(n) for n = 21566685507499 and 21566685507508.

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, 1148621072 + ... + 1148639847.

It is an arithmetic number, because the mean of its divisors is an integer number (3146481706760).

Almost surely, 2^{21566685507572} is an apocalyptic number.

It is an amenable number.

21566685507572 is a deficient number, since it is larger than the sum of its proper divisors (16191094973548).

21566685507572 is a wasteful number, since it uses less digits than its factorization.

21566685507572 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2297263270 (or 2297263268 counting only the distinct ones).

The product of its (nonzero) digits is 211680000, while the sum is 65.

The spelling of 21566685507572 in words is "twenty-one trillion, five hundred sixty-six billion, six hundred eighty-five million, five hundred seven thousand, five hundred seventy-two".