91137257 has 2 divisors, whose sum is σ = 91137258. Its totient is φ = 91137256.

The previous prime is 91137217. The next prime is 91137259. The reversal of 91137257 is 75273119.

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., 74580496 + 16556761 = 8636^2 + 4069^2 .

It is an emirp because it is prime and its reverse (75273119) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 91137257 - 2⁸ = 91137001 is a prime.

It is a super-2 number, since 2×91137257² = 16611999226968098, which contains 22 as substring.

Together with 91137259, 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 (91137259) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 45568628 + 45568629.

It is an arithmetic number, because the mean of its divisors is an integer number (45568629).

Almost surely, 2^91137257 is an apocalyptic number.

It is an amenable number.

91137257 is a deficient number, since it is larger than the sum of its proper divisors (1).

91137257 is an equidigital number, since it uses as much as digits as its factorization.

91137257 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 13230, while the sum is 35.

The square root of 91137257 is about 9546.5835250104. The cubic root of 91137257 is about 450.0201752271.

The spelling of 91137257 in words is "ninety-one million, one hundred thirty-seven thousand, two hundred fifty-seven".