91907405581 has 2 divisors, whose sum is σ = 91907405582. Its totient is φ = 91907405580.

The previous prime is 91907405561. The next prime is 91907405659. The reversal of 91907405581 is 18550470919.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 46779201225 + 45128204356 = 216285^2 + 212434^2 .

It is a cyclic number.

It is not a de Polignac number, because 91907405581 - 2⁹ = 91907405069 is a prime.

It is a super-2 number, since 2×91907405581² (a number of 23 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (91907405561) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 45953702790 + 45953702791.

It is an arithmetic number, because the mean of its divisors is an integer number (45953702791).

Almost surely, 2^91907405581 is an apocalyptic number.

It is an amenable number.

91907405581 is a deficient number, since it is larger than the sum of its proper divisors (1).

91907405581 is an equidigital number, since it uses as much as digits as its factorization.

91907405581 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 453600, while the sum is 49.

The spelling of 91907405581 in words is "ninety-one billion, nine hundred seven million, four hundred five thousand, five hundred eighty-one".