21644582974 has 64 divisors (see below), whose sum is σ = 39856914432. Its totient is φ = 8619811200.

The previous prime is 21644582957. The next prime is 21644582987. The reversal of 21644582974 is 47928544612.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 1071084 + ... + 1091104.

It is an arithmetic number, because the mean of its divisors is an integer number (622764288).

Almost surely, 2^21644582974 is an apocalyptic number.

21644582974 is a deficient number, since it is larger than the sum of its proper divisors (18212331458).

21644582974 is a wasteful number, since it uses less digits than its factorization.

21644582974 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 20161.

The product of its digits is 3870720, while the sum is 52.

The spelling of 21644582974 in words is "twenty-one billion, six hundred forty-four million, five hundred eighty-two thousand, nine hundred seventy-four".