21944621615 has 64 divisors (see below), whose sum is σ = 34003722240. Its totient is φ = 13232885760.

The previous prime is 21944621603. The next prime is 21944621693. The reversal of 21944621615 is 51612644912.

It is not a de Polignac number, because 21944621615 - 2⁸ = 21944621359 is a prime.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 811970 + ... + 838560.

It is an arithmetic number, because the mean of its divisors is an integer number (531308160).

Almost surely, 2^21944621615 is an apocalyptic number.

21944621615 is a deficient number, since it is larger than the sum of its proper divisors (12059100625).

21944621615 is a wasteful number, since it uses less digits than its factorization.

21944621615 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 26712.

The product of its digits is 103680, while the sum is 41.

The spelling of 21944621615 in words is "twenty-one billion, nine hundred forty-four million, six hundred twenty-one thousand, six hundred fifteen".