91431281 has 4 divisors (see below), whose sum is σ = 92089200. Its totient is φ = 90773364.

The previous prime is 91431257. The next prime is 91431283. The reversal of 91431281 is 18213419.

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.

It is a cyclic number.

It is not a de Polignac number, because 91431281 - 2¹⁸ = 91169137 is a prime.

It is a super-2 number, since 2×91431281² = 16719358290601922, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (91431283) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 328751 + ... + 329028.

It is an arithmetic number, because the mean of its divisors is an integer number (23022300).

Almost surely, 2^91431281 is an apocalyptic number.

It is an amenable number.

91431281 is a deficient number, since it is larger than the sum of its proper divisors (657919).

91431281 is a wasteful number, since it uses less digits than its factorization.

91431281 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 657918.

The product of its digits is 1728, while the sum is 29.

The square root of 91431281 is about 9561.9705605069. The cubic root of 91431281 is about 450.5036024551.

The spelling of 91431281 in words is "ninety-one million, four hundred thirty-one thousand, two hundred eighty-one".