91312237 has 2 divisors, whose sum is σ = 91312238. Its totient is φ = 91312236.

The previous prime is 91312217. The next prime is 91312241. The reversal of 91312237 is 73221319.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 85581001 + 5731236 = 9251^2 + 2394^2 .

It is an emirp because it is prime and its reverse (73221319) is a distict prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-91312237 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (91312217) 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, 45656118 + 45656119.

It is an arithmetic number, because the mean of its divisors is an integer number (45656119).

Almost surely, 2^91312237 is an apocalyptic number.

It is an amenable number.

91312237 is a deficient number, since it is larger than the sum of its proper divisors (1).

91312237 is an equidigital number, since it uses as much as digits as its factorization.

91312237 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 2268, while the sum is 28.

The square root of 91312237 is about 9555.7436654611. The cubic root of 91312237 is about 450.3079981990.

The spelling of 91312237 in words is "ninety-one million, three hundred twelve thousand, two hundred thirty-seven".