91868591 has 8 divisors (see below), whose sum is σ = 98148480. Its totient is φ = 85733208.

The previous prime is 91868587. The next prime is 91868627. The reversal of 91868591 is 19586819.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 91868591 - 2² = 91868587 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 (91868191) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 34811 + ... + 37356.

It is an arithmetic number, because the mean of its divisors is an integer number (12268560).

Almost surely, 2^91868591 is an apocalyptic number.

91868591 is a deficient number, since it is larger than the sum of its proper divisors (6279889).

91868591 is a wasteful number, since it uses less digits than its factorization.

91868591 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 72253.

The product of its digits is 155520, while the sum is 47.

The square root of 91868591 is about 9584.8104310936. The cubic root of 91868591 is about 451.2207037403.

The spelling of 91868591 in words is "ninety-one million, eight hundred sixty-eight thousand, five hundred ninety-one".