21566266512 has 60 divisors (see below), whose sum is σ = 64808838576. Its totient is φ = 6161789760.

The previous prime is 21566266499. The next prime is 21566266567.

It is a happy number.

21566266512 is nontrivially palindromic in base 10.

It is a super-2 number, since 2×21566266512² (a number of 21 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (42).

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 4582314 + ... + 4587017.

Almost surely, 2^21566266512 is an apocalyptic number.

It is an amenable number.

21566266512 is an abundant number, since it is smaller than the sum of its proper divisors (43242572064).

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

21566266512 is a wasteful number, since it uses less digits than its factorization.

21566266512 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9169356 (or 9169343 counting only the distinct ones).

The product of its digits is 259200, while the sum is 42.

The spelling of 21566266512 in words is "twenty-one billion, five hundred sixty-six million, two hundred sixty-six thousand, five hundred twelve".