91097971 has 2 divisors, whose sum is σ = 91097972. Its totient is φ = 91097970.

The previous prime is 91097969. The next prime is 91097987. The reversal of 91097971 is 17979019.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 91097971 - 2¹ = 91097969 is a prime.

Together with 91097969, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (91097921) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 45548985 + 45548986.

It is an arithmetic number, because the mean of its divisors is an integer number (45548986).

Almost surely, 2^91097971 is an apocalyptic number.

91097971 is a deficient number, since it is larger than the sum of its proper divisors (1).

91097971 is an equidigital number, since it uses as much as digits as its factorization.

91097971 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 35721, while the sum is 43.

The square root of 91097971 is about 9544.5257084886. The cubic root of 91097971 is about 449.9555034192.

The spelling of 91097971 in words is "ninety-one million, ninety-seven thousand, nine hundred seventy-one".