91471347581 has 2 divisors, whose sum is σ = 91471347582. Its totient is φ = 91471347580.

The previous prime is 91471347523. The next prime is 91471347601. The reversal of 91471347581 is 18574317419.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 90294240100 + 1177107481 = 300490^2 + 34309^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-91471347581 is a prime.

It is a super-2 number, since 2×91471347581² (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 (91471347521) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 45735673790 + 45735673791.

It is an arithmetic number, because the mean of its divisors is an integer number (45735673791).

Almost surely, 2^91471347581 is an apocalyptic number.

It is an amenable number.

91471347581 is a deficient number, since it is larger than the sum of its proper divisors (1).

91471347581 is an equidigital number, since it uses as much as digits as its factorization.

91471347581 is an evil number, because the sum of its binary digits is even.

The product of its digits is 846720, while the sum is 50.

The spelling of 91471347581 in words is "ninety-one billion, four hundred seventy-one million, three hundred forty-seven thousand, five hundred eighty-one".