91864621 has 4 divisors (see below), whose sum is σ = 92246044. Its totient is φ = 91483200.

The previous prime is 91864613. The next prime is 91864631. The reversal of 91864621 is 12646819.

It is a happy number.

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 28836900 + 63027721 = 5370^2 + 7939^2 .

It is a cyclic number.

It is not a de Polignac number, because 91864621 - 2³ = 91864613 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 (91864631) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 190350 + ... + 190831.

It is an arithmetic number, because the mean of its divisors is an integer number (23061511).

Almost surely, 2^91864621 is an apocalyptic number.

It is an amenable number.

91864621 is a deficient number, since it is larger than the sum of its proper divisors (381423).

91864621 is a wasteful number, since it uses less digits than its factorization.

91864621 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 381422.

The product of its digits is 20736, while the sum is 37.

The square root of 91864621 is about 9584.6033303418. The cubic root of 91864621 is about 451.2142039780.

The spelling of 91864621 in words is "ninety-one million, eight hundred sixty-four thousand, six hundred twenty-one".