91795721 has 2 divisors, whose sum is σ = 91795722. Its totient is φ = 91795720.

The previous prime is 91795661. The next prime is 91795723. The reversal of 91795721 is 12759719.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 91776400 + 19321 = 9580^2 + 139^2 .

It is a cyclic number.

It is not a de Polignac number, because 91795721 - 2⁶ = 91795657 is a prime.

Together with 91795723, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (91795723) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 45897860 + 45897861.

It is an arithmetic number, because the mean of its divisors is an integer number (45897861).

Almost surely, 2^91795721 is an apocalyptic number.

It is an amenable number.

91795721 is a deficient number, since it is larger than the sum of its proper divisors (1).

91795721 is an equidigital number, since it uses as much as digits as its factorization.

91795721 is an evil number, because the sum of its binary digits is even.

The product of its digits is 39690, while the sum is 41.

The square root of 91795721 is about 9581.0083498555. The cubic root of 91795721 is about 451.1013697012.

The spelling of 91795721 in words is "ninety-one million, seven hundred ninety-five thousand, seven hundred twenty-one".