91331887 has 4 divisors (see below), whose sum is σ = 93559536. Its totient is φ = 89104240.

The previous prime is 91331881. The next prime is 91331899. The reversal of 91331887 is 78813319.

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

It is a cyclic number.

It is not a de Polignac number, because 91331887 - 2¹¹ = 91329839 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (91331881) 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, 1113763 + ... + 1113844.

It is an arithmetic number, because the mean of its divisors is an integer number (23389884).

Almost surely, 2^91331887 is an apocalyptic number.

91331887 is a deficient number, since it is larger than the sum of its proper divisors (2227649).

91331887 is a wasteful number, since it uses less digits than its factorization.

91331887 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2227648.

The product of its digits is 36288, while the sum is 40.

The square root of 91331887 is about 9556.7717875860. The cubic root of 91331887 is about 450.3402973293.

The spelling of 91331887 in words is "ninety-one million, three hundred thirty-one thousand, eight hundred eighty-seven".