91771961 has 2 divisors, whose sum is σ = 91771962. Its totient is φ = 91771960.

The previous prime is 91771903. The next prime is 91771969. The reversal of 91771961 is 16917719.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 69822736 + 21949225 = 8356^2 + 4685^2 .

It is a cyclic number.

It is not a de Polignac number, because 91771961 - 2²² = 87577657 is a prime.

It is not a weakly prime, because it can be changed into another prime (91771969) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 45885980 + 45885981.

It is an arithmetic number, because the mean of its divisors is an integer number (45885981).

Almost surely, 2^91771961 is an apocalyptic number.

It is an amenable number.

91771961 is a deficient number, since it is larger than the sum of its proper divisors (1).

91771961 is an equidigital number, since it uses as much as digits as its factorization.

91771961 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 23814, while the sum is 41.

The square root of 91771961 is about 9579.7683166139. The cubic root of 91771961 is about 451.0624459790.

The spelling of 91771961 in words is "ninety-one million, seven hundred seventy-one thousand, nine hundred sixty-one".