91313450581 has 2 divisors, whose sum is σ = 91313450582. Its totient is φ = 91313450580.

The previous prime is 91313450519. The next prime is 91313450647. The reversal of 91313450581 is 18505431319.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 90944464900 + 368985681 = 301570^2 + 19209^2 .

It is an emirp because it is prime and its reverse (18505431319) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 91313450581 - 2¹¹ = 91313448533 is a prime.

It is a super-2 number, since 2×91313450581² (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 (91313450681) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 45656725290 + 45656725291.

It is an arithmetic number, because the mean of its divisors is an integer number (45656725291).

Almost surely, 2^91313450581 is an apocalyptic number.

It is an amenable number.

91313450581 is a deficient number, since it is larger than the sum of its proper divisors (1).

91313450581 is an equidigital number, since it uses as much as digits as its factorization.

91313450581 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 64800, while the sum is 40.

The spelling of 91313450581 in words is "ninety-one billion, three hundred thirteen million, four hundred fifty thousand, five hundred eighty-one".