21252772666 has 32 divisors (see below), whose sum is σ = 34186235328. Its totient is φ = 9873534720.

The previous prime is 21252772643. The next prime is 21252772679. The reversal of 21252772666 is 66627725212.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 6717601 + ... + 6720763.

It is an arithmetic number, because the mean of its divisors is an integer number (1068319854).

Almost surely, 2^21252772666 is an apocalyptic number.

21252772666 is a deficient number, since it is larger than the sum of its proper divisors (12933462662).

21252772666 is a wasteful number, since it uses less digits than its factorization.

21252772666 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5646.

The product of its digits is 846720, while the sum is 46.

The spelling of 21252772666 in words is "twenty-one billion, two hundred fifty-two million, seven hundred seventy-two thousand, six hundred sixty-six".