86721640961 has 2 divisors, whose sum is σ = 86721640962. Its totient is φ = 86721640960.

The previous prime is 86721640913. The next prime is 86721640997. The reversal of 86721640961 is 16904612768.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 59995603600 + 26726037361 = 244940^2 + 163481^2 .

It is a cyclic number.

It is not a de Polignac number, because 86721640961 - 2²² = 86717446657 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 (86721640261) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 43360820480 + 43360820481.

It is an arithmetic number, because the mean of its divisors is an integer number (43360820481).

Almost surely, 2^86721640961 is an apocalyptic number.

It is an amenable number.

86721640961 is a deficient number, since it is larger than the sum of its proper divisors (1).

86721640961 is an equidigital number, since it uses as much as digits as its factorization.

86721640961 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 870912, while the sum is 50.

The spelling of 86721640961 in words is "eighty-six billion, seven hundred twenty-one million, six hundred forty thousand, nine hundred sixty-one".