91981216 has 24 divisors (see below), whose sum is σ = 186931584. Its totient is φ = 44506560.

The previous prime is 91981213. The next prime is 91981217. The reversal of 91981216 is 61218919.

It is a Smith number, since the sum of its digits (37) coincides with the sum of the digits of its prime factors.

It is not an unprimeable number, because it can be changed into a prime (91981213) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 45370 + ... + 47353.

It is an arithmetic number, because the mean of its divisors is an integer number (7788816).

Almost surely, 2^91981216 is an apocalyptic number.

It is an amenable number.

91981216 is an abundant number, since it is smaller than the sum of its proper divisors (94950368).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

91981216 is a wasteful number, since it uses less digits than its factorization.

91981216 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 92764 (or 92756 counting only the distinct ones).

The product of its digits is 7776, while the sum is 37.

The square root of 91981216 is about 9590.6838129510. The cubic root of 91981216 is about 451.4050176554.

The spelling of 91981216 in words is "ninety-one million, nine hundred eighty-one thousand, two hundred sixteen".