91931616 has 144 divisors (see below), whose sum is σ = 308625408. Its totient is φ = 25401600.

The previous prime is 91931573. The next prime is 91931629. The reversal of 91931616 is 61613919.

91931616 is a `hidden beast` number, since 9 + 1 + 9 + 31 + 616 = 666.

It is a tau number, because it is divible by the number of its divisors (144).

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a nude number because it is divisible by every one of its digits.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 61761 + ... + 63231.

It is an arithmetic number, because the mean of its divisors is an integer number (2143232).

Almost surely, 2^91931616 is an apocalyptic number.

91931616 is a gapful number since it is divisible by the number (96) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 91931616, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (154312704).

91931616 is an abundant number, since it is smaller than the sum of its proper divisors (216693792).

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

91931616 is a wasteful number, since it uses less digits than its factorization.

91931616 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1525 (or 1514 counting only the distinct ones).

The product of its digits is 8748, while the sum is 36.

The square root of 91931616 is about 9588.0976215306. The cubic root of 91931616 is about 451.3238644391.

The spelling of 91931616 in words is "ninety-one million, nine hundred thirty-one thousand, six hundred sixteen".