91291973 has 2 divisors, whose sum is σ = 91291974. Its totient is φ = 91291972.

The previous prime is 91291961. The next prime is 91292009. The reversal of 91291973 is 37919219.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 79887844 + 11404129 = 8938^2 + 3377^2 .

It is a cyclic number.

It is not a de Polignac number, because 91291973 - 2¹⁴ = 91275589 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 91291973.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (91291933) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 45645986 + 45645987.

It is an arithmetic number, because the mean of its divisors is an integer number (45645987).

Almost surely, 2^91291973 is an apocalyptic number.

It is an amenable number.

91291973 is a deficient number, since it is larger than the sum of its proper divisors (1).

91291973 is an equidigital number, since it uses as much as digits as its factorization.

91291973 is an evil number, because the sum of its binary digits is even.

The product of its digits is 30618, while the sum is 41.

The square root of 91291973 is about 9554.6833019206. The cubic root of 91291973 is about 450.2746849700.

The spelling of 91291973 in words is "ninety-one million, two hundred ninety-one thousand, nine hundred seventy-three".