91971844 has 12 divisors (see below), whose sum is σ = 161460684. Its totient is φ = 45840224.

The previous prime is 91971839. The next prime is 91971877. The reversal of 91971844 is 44817919.

It can be written as a sum of positive squares in 2 ways, for example, as 37063744 + 54908100 = 6088^2 + 7410^2 .

It is a super-3 number, since 3×91971844³ (a number of 25 digits) contains 333 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 91971844.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 34999 + ... + 37534.

It is an arithmetic number, because the mean of its divisors is an integer number (13455057).

Almost surely, 2^91971844 is an apocalyptic number.

It is an amenable number.

91971844 is a deficient number, since it is larger than the sum of its proper divisors (69488840).

91971844 is a wasteful number, since it uses less digits than its factorization.

91971844 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 72854 (or 72852 counting only the distinct ones).

The product of its digits is 72576, while the sum is 43.

The square root of 91971844 is about 9590.1952013502. The cubic root of 91971844 is about 451.3896858601.

The spelling of 91971844 in words is "ninety-one million, nine hundred seventy-one thousand, eight hundred forty-four".