91165421 has 2 divisors, whose sum is σ = 91165422. Its totient is φ = 91165420.

The previous prime is 91165397. The next prime is 91165429. The reversal of 91165421 is 12456119.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 49420900 + 41744521 = 7030^2 + 6461^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-91165421 is a prime.

It is a super-2 number, since 2×91165421² = 16622267972214482, 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 (91165429) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 45582710 + 45582711.

It is an arithmetic number, because the mean of its divisors is an integer number (45582711).

Almost surely, 2^91165421 is an apocalyptic number.

It is an amenable number.

91165421 is a deficient number, since it is larger than the sum of its proper divisors (1).

91165421 is an equidigital number, since it uses as much as digits as its factorization.

91165421 is an evil number, because the sum of its binary digits is even.

The product of its digits is 2160, while the sum is 29.

The square root of 91165421 is about 9548.0584937463. The cubic root of 91165421 is about 450.0665267899.

The spelling of 91165421 in words is "ninety-one million, one hundred sixty-five thousand, four hundred twenty-one".