21652621605 has 12 divisors (see below), whose sum is σ = 37531210860. Its totient is φ = 11548064832.

The previous prime is 21652621583. The next prime is 21652621609. The reversal of 21652621605 is 50612625612.

21652621605 is a `hidden beast` number, since 2 + 1 + 6 + 5 + 26 + 21 + 605 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 6763253121 + 14889368484 = 82239^2 + 122022^2 .

It is not a de Polignac number, because 21652621605 - 2²³ = 21644232997 is a prime.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 21652621605.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21652621609) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 240584640 + ... + 240584729.

It is an arithmetic number, because the mean of its divisors is an integer number (3127600905).

Almost surely, 2^21652621605 is an apocalyptic number.

It is an amenable number.

21652621605 is a deficient number, since it is larger than the sum of its proper divisors (15878589255).

21652621605 is a wasteful number, since it uses less digits than its factorization.

21652621605 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 481169380 (or 481169377 counting only the distinct ones).

The product of its (nonzero) digits is 43200, while the sum is 36.

The spelling of 21652621605 in words is "twenty-one billion, six hundred fifty-two million, six hundred twenty-one thousand, six hundred five".