91228231 has 2 divisors, whose sum is σ = 91228232. Its totient is φ = 91228230.

The previous prime is 91228223. The next prime is 91228237. The reversal of 91228231 is 13282219.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 91228231 - 2³ = 91228223 is a prime.

It is a super-2 number, since 2×91228231² = 16645180262778722, which contains 22 as substring.

It is equal to p_5284144 and since 91228231 and 5284144 have the same sum of digits, it is a Honaker prime.

It is a self number, because there is not a number n which added to its sum of digits gives 91228231.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (91228237) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 45614115 + 45614116.

It is an arithmetic number, because the mean of its divisors is an integer number (45614116).

Almost surely, 2^91228231 is an apocalyptic number.

91228231 is a deficient number, since it is larger than the sum of its proper divisors (1).

91228231 is an equidigital number, since it uses as much as digits as its factorization.

91228231 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1728, while the sum is 28.

The square root of 91228231 is about 9551.3470777687. The cubic root of 91228231 is about 450.1698634449.

The spelling of 91228231 in words is "ninety-one million, two hundred twenty-eight thousand, two hundred thirty-one".