91247971 has 2 divisors, whose sum is σ = 91247972. Its totient is φ = 91247970.

The previous prime is 91247953. The next prime is 91247983. The reversal of 91247971 is 17974219.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 91247971 - 2⁷ = 91247843 is a prime.

It is not a weakly prime, because it can be changed into another prime (91247071) 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, 45623985 + 45623986.

It is an arithmetic number, because the mean of its divisors is an integer number (45623986).

Almost surely, 2^91247971 is an apocalyptic number.

91247971 is a deficient number, since it is larger than the sum of its proper divisors (1).

91247971 is an equidigital number, since it uses as much as digits as its factorization.

91247971 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 31752, while the sum is 40.

The square root of 91247971 is about 9552.3803839671. The cubic root of 91247971 is about 450.2023304131.

The spelling of 91247971 in words is "ninety-one million, two hundred forty-seven thousand, nine hundred seventy-one".