91917157 has 2 divisors, whose sum is σ = 91917158. Its totient is φ = 91917156.

The previous prime is 91917151. The next prime is 91917191. The reversal of 91917157 is 75171919.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 91221601 + 695556 = 9551^2 + 834^2 .

It is an emirp because it is prime and its reverse (75171919) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 91917157 - 2⁷ = 91917029 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (91917151) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 45958578 + 45958579.

It is an arithmetic number, because the mean of its divisors is an integer number (45958579).

Almost surely, 2^91917157 is an apocalyptic number.

It is an amenable number.

91917157 is a deficient number, since it is larger than the sum of its proper divisors (1).

91917157 is an equidigital number, since it uses as much as digits as its factorization.

91917157 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 19845, while the sum is 40.

The square root of 91917157 is about 9587.3435841217. The cubic root of 91917157 is about 451.3002018002.

The spelling of 91917157 in words is "ninety-one million, nine hundred seventeen thousand, one hundred fifty-seven".