91164581 has 2 divisors, whose sum is σ = 91164582. Its totient is φ = 91164580.

The previous prime is 91164551. The next prime is 91164613. The reversal of 91164581 is 18546119.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 81739681 + 9424900 = 9041^2 + 3070^2 .

It is a cyclic number.

It is not a de Polignac number, because 91164581 - 2¹⁰ = 91163557 is a prime.

It is a super-2 number, since 2×91164581² = 16621961657811122, which contains 22 as substring.

It is a Sophie Germain prime.

It is a Chen prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (91164551) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 45582290 + 45582291.

It is an arithmetic number, because the mean of its divisors is an integer number (45582291).

Almost surely, 2^91164581 is an apocalyptic number.

It is an amenable number.

91164581 is a deficient number, since it is larger than the sum of its proper divisors (1).

91164581 is an equidigital number, since it uses as much as digits as its factorization.

91164581 is an evil number, because the sum of its binary digits is even.

The product of its digits is 8640, while the sum is 35.

The square root of 91164581 is about 9548.0145056446. The cubic root of 91164581 is about 450.0651444783.

The spelling of 91164581 in words is "ninety-one million, one hundred sixty-four thousand, five hundred eighty-one".