91689431 has 4 divisors (see below), whose sum is σ = 95675952. Its totient is φ = 87702912.

The previous prime is 91689391. The next prime is 91689439. The reversal of 91689431 is 13498619.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-91689431 is a prime.

It is a super-2 number, since 2×91689431² = 16813903514207522, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (91689439) 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, 1993226 + ... + 1993271.

It is an arithmetic number, because the mean of its divisors is an integer number (23918988).

Almost surely, 2^91689431 is an apocalyptic number.

91689431 is a deficient number, since it is larger than the sum of its proper divisors (3986521).

91689431 is a wasteful number, since it uses less digits than its factorization.

91689431 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3986520.

The product of its digits is 46656, while the sum is 41.

The square root of 91689431 is about 9575.4598323005. The cubic root of 91689431 is about 450.9271928002.

The spelling of 91689431 in words is "ninety-one million, six hundred eighty-nine thousand, four hundred thirty-one".