91921864 has 16 divisors (see below), whose sum is σ = 172663920. Its totient is φ = 45878160.

The previous prime is 91921861. The next prime is 91921871. The reversal of 91921864 is 46812919.

It is not an unprimeable number, because it can be changed into a prime (91921861) 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, 5494 + ... + 14629.

It is an arithmetic number, because the mean of its divisors is an integer number (10791495).

Almost surely, 2^91921864 is an apocalyptic number.

It is an amenable number.

91921864 is a deficient number, since it is larger than the sum of its proper divisors (80742056).

91921864 is a wasteful number, since it uses less digits than its factorization.

91921864 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 20700 (or 20696 counting only the distinct ones).

The product of its digits is 31104, while the sum is 40.

The square root of 91921864 is about 9587.5890608641. The cubic root of 91921864 is about 451.3079052361.

The spelling of 91921864 in words is "ninety-one million, nine hundred twenty-one thousand, eight hundred sixty-four".