21975722658 has 90 divisors (see below), whose sum is σ = 52054898049. Its totient is φ = 6928381008.

The previous prime is 21975722641. The next prime is 21975722663. The reversal of 21975722658 is 85622757912.

21975722658 is a `hidden beast` number, since 2 + 1 + 9 + 7 + 572 + 2 + 65 + 8 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 12240545769 + 9735176889 = 110637^2 + 98667^2 .

It is an ABA number since it can be written as A⋅B^A, here for A=2, B=104823.

It is a Smith number, since the sum of its digits (54) coincides with the sum of the digits of its prime factors.

It is a Harshad number since it is a multiple of its sum of digits (54).

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 44 ways as a sum of consecutive naturals, for example, 35849160 + ... + 35849772.

Almost surely, 2^21975722658 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21975722658

21975722658 is an abundant number, since it is smaller than the sum of its proper divisors (30079175391).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21975722658 is an frugal number, since it uses more digits than its factorization.

21975722658 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1278 (or 637 counting only the distinct ones).

The product of its digits is 4233600, while the sum is 54.

The spelling of 21975722658 in words is "twenty-one billion, nine hundred seventy-five million, seven hundred twenty-two thousand, six hundred fifty-eight".