91433281 has 4 divisors (see below), whose sum is σ = 91455364. Its totient is φ = 91411200.

The previous prime is 91433249. The next prime is 91433297. The reversal of 91433281 is 18233419.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 12845056 + 78588225 = 3584^2 + 8865^2 .

It is a 3-Lehmer number, since φ(91433281) divides (91433281-1)³.

It is a cyclic number.

It is not a de Polignac number, because 91433281 - 2⁵ = 91433249 is a prime.

It is a super-2 number, since 2×91433281² = 16720089748849922, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (91433081) 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, 2760 + ... + 13801.

It is an arithmetic number, because the mean of its divisors is an integer number (22863841).

It is a Poulet number, since it divides 2^91433280-1.

Almost surely, 2^91433281 is an apocalyptic number.

91433281 is the 5521-st octagonal number.

It is an amenable number.

91433281 is a deficient number, since it is larger than the sum of its proper divisors (22083).

91433281 is a wasteful number, since it uses less digits than its factorization.

91433281 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 22082.

The product of its digits is 5184, while the sum is 31.

The square root of 91433281 is about 9562.0751408886. The cubic root of 91433281 is about 450.5068872559.

The spelling of 91433281 in words is "ninety-one million, four hundred thirty-three thousand, two hundred eighty-one".