21655212566615 has 16 divisors (see below), whose sum is σ = 26678102630400. Its totient is φ = 16866798034080.

The previous prime is 21655212566591. The next prime is 21655212566623. The reversal of 21655212566615 is 51666521255612.

It is not a de Polignac number, because 21655212566615 - 2¹⁶ = 21655212501079 is a prime.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 241185065 + ... + 241274834.

It is an arithmetic number, because the mean of its divisors is an integer number (1667381414400).

Almost surely, 2^{21655212566615} is an apocalyptic number.

21655212566615 is a deficient number, since it is larger than the sum of its proper divisors (5022890063785).

21655212566615 is a wasteful number, since it uses less digits than its factorization.

21655212566615 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 482460142.

The product of its digits is 6480000, while the sum is 53.

The spelling of 21655212566615 in words is "twenty-one trillion, six hundred fifty-five billion, two hundred twelve million, five hundred sixty-six thousand, six hundred fifteen".