91231243 has 2 divisors, whose sum is σ = 91231244. Its totient is φ = 91231242.

The previous prime is 91231241. The next prime is 91231249. The reversal of 91231243 is 34213219.

It is a weak prime.

It is an emirp because it is prime and its reverse (34213219) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 91231243 - 2¹ = 91231241 is a prime.

Together with 91231241, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (91231241) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 45615621 + 45615622.

It is an arithmetic number, because the mean of its divisors is an integer number (45615622).

Almost surely, 2^91231243 is an apocalyptic number.

91231243 is a deficient number, since it is larger than the sum of its proper divisors (1).

91231243 is an equidigital number, since it uses as much as digits as its factorization.

91231243 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1296, while the sum is 25.

The square root of 91231243 is about 9551.5047505616. The cubic root of 91231243 is about 450.1748176741.

The spelling of 91231243 in words is "ninety-one million, two hundred thirty-one thousand, two hundred forty-three".