21659146961 has 2 divisors, whose sum is σ = 21659146962. Its totient is φ = 21659146960.

The previous prime is 21659146937. The next prime is 21659147063. The reversal of 21659146961 is 16964195612.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 21416566336 + 242580625 = 146344^2 + 15575^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21659146961 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (21659046961) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10829573480 + 10829573481.

It is an arithmetic number, because the mean of its divisors is an integer number (10829573481).

Almost surely, 2^21659146961 is an apocalyptic number.

It is an amenable number.

21659146961 is a deficient number, since it is larger than the sum of its proper divisors (1).

21659146961 is an equidigital number, since it uses as much as digits as its factorization.

21659146961 is an evil number, because the sum of its binary digits is even.

The product of its digits is 699840, while the sum is 50.

The spelling of 21659146961 in words is "twenty-one billion, six hundred fifty-nine million, one hundred forty-six thousand, nine hundred sixty-one".