21956525361 has 8 divisors (see below), whose sum is σ = 32528185760. Its totient is φ = 14637683556.

The previous prime is 21956525317. The next prime is 21956525411. The reversal of 21956525361 is 16352565912.

21956525361 is a `hidden beast` number, since 2 + 1 + 9 + 565 + 25 + 3 + 61 = 666.

It is not a de Polignac number, because 21956525361 - 2²³ = 21948136753 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21956525561) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 406602295 + ... + 406602348.

It is an arithmetic number, because the mean of its divisors is an integer number (4066023220).

Almost surely, 2^21956525361 is an apocalyptic number.

It is an amenable number.

21956525361 is a deficient number, since it is larger than the sum of its proper divisors (10571660399).

21956525361 is an equidigital number, since it uses as much as digits as its factorization.

21956525361 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 813204652 (or 813204646 counting only the distinct ones).

The product of its digits is 486000, while the sum is 45.

The spelling of 21956525361 in words is "twenty-one billion, nine hundred fifty-six million, five hundred twenty-five thousand, three hundred sixty-one".