91223257 has 4 divisors (see below), whose sum is σ = 91282896. Its totient is φ = 91163620.

The previous prime is 91223227. The next prime is 91223261. The reversal of 91223257 is 75232219.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 75232219 = 479 ⋅157061.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-91223257 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (91223227) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 27463 + ... + 30604.

It is an arithmetic number, because the mean of its divisors is an integer number (22820724).

Almost surely, 2^91223257 is an apocalyptic number.

It is an amenable number.

91223257 is a deficient number, since it is larger than the sum of its proper divisors (59639).

91223257 is a wasteful number, since it uses less digits than its factorization.

91223257 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 59638.

The product of its digits is 7560, while the sum is 31.

The square root of 91223257 is about 9551.0866920995. The cubic root of 91223257 is about 450.1616818196.

The spelling of 91223257 in words is "ninety-one million, two hundred twenty-three thousand, two hundred fifty-seven".