91565261 has 2 divisors, whose sum is σ = 91565262. Its totient is φ = 91565260.

The previous prime is 91565251. The next prime is 91565293. The reversal of 91565261 is 16256519.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 85285225 + 6280036 = 9235^2 + 2506^2 .

It is a cyclic number.

It is not a de Polignac number, because 91565261 - 2⁶ = 91565197 is a prime.

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 (91565251) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 45782630 + 45782631.

It is an arithmetic number, because the mean of its divisors is an integer number (45782631).

Almost surely, 2^91565261 is an apocalyptic number.

It is an amenable number.

91565261 is a deficient number, since it is larger than the sum of its proper divisors (1).

91565261 is an equidigital number, since it uses as much as digits as its factorization.

91565261 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 16200, while the sum is 35.

The square root of 91565261 is about 9568.9738739324. The cubic root of 91565261 is about 450.7235454681.

The spelling of 91565261 in words is "ninety-one million, five hundred sixty-five thousand, two hundred sixty-one".