21718372156 has 12 divisors (see below), whose sum is σ = 40930778392. Its totient is φ = 10023864048.

The previous prime is 21718372139. The next prime is 21718372201. The reversal of 21718372156 is 65127381712.

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, 208830450 + ... + 208830553.

Almost surely, 2^21718372156 is an apocalyptic number.

21718372156 is a gapful number since it is divisible by the number (26) formed by its first and last digit.

It is an amenable number.

21718372156 is a deficient number, since it is larger than the sum of its proper divisors (19212406236).

21718372156 is a wasteful number, since it uses less digits than its factorization.

21718372156 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 417661020 (or 417661018 counting only the distinct ones).

The product of its digits is 141120, while the sum is 43.

The spelling of 21718372156 in words is "twenty-one billion, seven hundred eighteen million, three hundred seventy-two thousand, one hundred fifty-six".