21233637666 has 72 divisors (see below), whose sum is σ = 46747589616. Its totient is φ = 6965478000.

The previous prime is 21233637613. The next prime is 21233637679. The reversal of 21233637666 is 66673633212.

It is an unprimeable number.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 47931241 + ... + 47931683.

It is an arithmetic number, because the mean of its divisors is an integer number (649272078).

Almost surely, 2^21233637666 is an apocalyptic number.

21233637666 is an abundant number, since it is smaller than the sum of its proper divisors (25513951950).

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

21233637666 is a wasteful number, since it uses less digits than its factorization.

21233637666 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 908 (or 802 counting only the distinct ones).

The product of its digits is 979776, while the sum is 45.

The spelling of 21233637666 in words is "twenty-one billion, two hundred thirty-three million, six hundred thirty-seven thousand, six hundred sixty-six".