91431313 has 2 divisors, whose sum is σ = 91431314. Its totient is φ = 91431312.

The previous prime is 91431293. The next prime is 91431323. The reversal of 91431313 is 31313419.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 80784144 + 10647169 = 8988^2 + 3263^2 .

It is a cyclic number.

It is not a de Polignac number, because 91431313 - 2¹³ = 91423121 is a prime.

It is not a weakly prime, because it can be changed into another prime (91431323) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 45715656 + 45715657.

It is an arithmetic number, because the mean of its divisors is an integer number (45715657).

Almost surely, 2^91431313 is an apocalyptic number.

It is an amenable number.

91431313 is a deficient number, since it is larger than the sum of its proper divisors (1).

91431313 is an equidigital number, since it uses as much as digits as its factorization.

91431313 is an evil number, because the sum of its binary digits is even.

The product of its digits is 972, while the sum is 25.

The square root of 91431313 is about 9561.9722338020. The cubic root of 91431313 is about 450.5036550122.

The spelling of 91431313 in words is "ninety-one million, four hundred thirty-one thousand, three hundred thirteen".