91684395581 has 2 divisors, whose sum is σ = 91684395582. Its totient is φ = 91684395580.

The previous prime is 91684395521. The next prime is 91684395623. The reversal of 91684395581 is 18559348619.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 91297644025 + 386751556 = 302155^2 + 19666^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-91684395581 is a prime.

It is a super-2 number, since 2×91684395581² (a number of 23 digits) contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 91684395581.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (91684395511) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 45842197790 + 45842197791.

It is an arithmetic number, because the mean of its divisors is an integer number (45842197791).

Almost surely, 2^91684395581 is an apocalyptic number.

It is an amenable number.

91684395581 is a deficient number, since it is larger than the sum of its proper divisors (1).

91684395581 is an equidigital number, since it uses as much as digits as its factorization.

91684395581 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 9331200, while the sum is 59.

The spelling of 91684395581 in words is "ninety-one billion, six hundred eighty-four million, three hundred ninety-five thousand, five hundred eighty-one".