91681169 has 2 divisors, whose sum is σ = 91681170. Its totient is φ = 91681168.

The previous prime is 91681157. The next prime is 91681171. The reversal of 91681169 is 96118619.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 75777025 + 15904144 = 8705^2 + 3988^2 .

It is a cyclic number.

It is not a de Polignac number, because 91681169 - 2⁸ = 91680913 is a prime.

It is a super-2 number, since 2×91681169² = 16810873498413122, which contains 22 as substring.

Together with 91681171, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (91681069) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 45840584 + 45840585.

It is an arithmetic number, because the mean of its divisors is an integer number (45840585).

Almost surely, 2^91681169 is an apocalyptic number.

It is an amenable number.

91681169 is a deficient number, since it is larger than the sum of its proper divisors (1).

91681169 is an equidigital number, since it uses as much as digits as its factorization.

91681169 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 23328, while the sum is 41.

The square root of 91681169 is about 9575.0284072686. The cubic root of 91681169 is about 450.9136482643.

The spelling of 91681169 in words is "ninety-one million, six hundred eighty-one thousand, one hundred sixty-nine".