21864956518 has 16 divisors (see below), whose sum is σ = 34190628480. Its totient is φ = 10475064000.

The previous prime is 21864956507. The next prime is 21864956567. The reversal of 21864956518 is 81565946812.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1739583 + ... + 1752106.

It is an arithmetic number, because the mean of its divisors is an integer number (2136914280).

Almost surely, 2^21864956518 is an apocalyptic number.

21864956518 is a deficient number, since it is larger than the sum of its proper divisors (12325671962).

21864956518 is a wasteful number, since it uses less digits than its factorization.

21864956518 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3491823.

The product of its digits is 4147200, while the sum is 55.

The spelling of 21864956518 in words is "twenty-one billion, eight hundred sixty-four million, nine hundred fifty-six thousand, five hundred eighteen".