91031971 has 2 divisors, whose sum is σ = 91031972. Its totient is φ = 91031970.

The previous prime is 91031921. The next prime is 91031977. The reversal of 91031971 is 17913019.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-91031971 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (91031977) 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, 45515985 + 45515986.

It is an arithmetic number, because the mean of its divisors is an integer number (45515986).

Almost surely, 2^91031971 is an apocalyptic number.

91031971 is a deficient number, since it is larger than the sum of its proper divisors (1).

91031971 is an equidigital number, since it uses as much as digits as its factorization.

91031971 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1701, while the sum is 31.

The square root of 91031971 is about 9541.0676027371. The cubic root of 91031971 is about 449.8468137028.

The spelling of 91031971 in words is "ninety-one million, thirty-one thousand, nine hundred seventy-one".