91685021 has 2 divisors, whose sum is σ = 91685022. Its totient is φ = 91685020.

The previous prime is 91685003. The next prime is 91685047. The reversal of 91685021 is 12058619.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 53071225 + 38613796 = 7285^2 + 6214^2 .

It is a cyclic number.

It is not a de Polignac number, because 91685021 - 2¹⁴ = 91668637 is a prime.

It is a super-2 number, since 2×91685021² = 16812286151540882, which contains 22 as substring.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (91685821) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 45842510 + 45842511.

It is an arithmetic number, because the mean of its divisors is an integer number (45842511).

Almost surely, 2^91685021 is an apocalyptic number.

It is an amenable number.

91685021 is a deficient number, since it is larger than the sum of its proper divisors (1).

91685021 is an equidigital number, since it uses as much as digits as its factorization.

91685021 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 4320, while the sum is 32.

The square root of 91685021 is about 9575.2295533841. The cubic root of 91685021 is about 450.9199632472.

The spelling of 91685021 in words is "ninety-one million, six hundred eighty-five thousand, twenty-one".