21973072815 has 48 divisors (see below), whose sum is σ = 40364539488. Its totient is φ = 11019368448.

The previous prime is 21973072783. The next prime is 21973072871. The reversal of 21973072815 is 51827037912.

It is not a de Polignac number, because 21973072815 - 2⁵ = 21973072783 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 846307 + ... + 871883.

It is an arithmetic number, because the mean of its divisors is an integer number (840927906).

Almost surely, 2^21973072815 is an apocalyptic number.

21973072815 is a deficient number, since it is larger than the sum of its proper divisors (18391466673).

21973072815 is a wasteful number, since it uses less digits than its factorization.

21973072815 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 26728 (or 26725 counting only the distinct ones).

The product of its (nonzero) digits is 211680, while the sum is 45.

The spelling of 21973072815 in words is "twenty-one billion, nine hundred seventy-three million, seventy-two thousand, eight hundred fifteen".