91337581 has 2 divisors, whose sum is σ = 91337582. Its totient is φ = 91337580.

The previous prime is 91337573. The next prime is 91337593. The reversal of 91337581 is 18573319.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 49928356 + 41409225 = 7066^2 + 6435^2 .

It is a cyclic number.

It is not a de Polignac number, because 91337581 - 2³ = 91337573 is a prime.

It is a super-2 number, since 2×91337581² = 16685107405863122, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 91337581.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (91337551) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 45668790 + 45668791.

It is an arithmetic number, because the mean of its divisors is an integer number (45668791).

Almost surely, 2^91337581 is an apocalyptic number.

It is an amenable number.

91337581 is a deficient number, since it is larger than the sum of its proper divisors (1).

91337581 is an equidigital number, since it uses as much as digits as its factorization.

91337581 is an evil number, because the sum of its binary digits is even.

The product of its digits is 22680, while the sum is 37.

The square root of 91337581 is about 9557.0696868862. The cubic root of 91337581 is about 450.3496558146.

The spelling of 91337581 in words is "ninety-one million, three hundred thirty-seven thousand, five hundred eighty-one".