91611980 has 48 divisors (see below), whose sum is σ = 204827616. Its totient is φ = 34298880.

The previous prime is 91611959. The next prime is 91611983. The reversal of 91611980 is 8911619.

It is a self number, because there is not a number n which added to its sum of digits gives 91611980.

It is not an unprimeable number, because it can be changed into a prime (91611983) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 71102 + ... + 72378.

It is an arithmetic number, because the mean of its divisors is an integer number (4267242).

Almost surely, 2^91611980 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 91611980, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (102413808).

91611980 is an abundant number, since it is smaller than the sum of its proper divisors (113215636).

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

91611980 is a wasteful number, since it uses less digits than its factorization.

91611980 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1514 (or 1512 counting only the distinct ones).

The product of its (nonzero) digits is 3888, while the sum is 35.

The square root of 91611980 is about 9571.4147334655. The cubic root of 91611980 is about 450.8001894295.

The spelling of 91611980 in words is "ninety-one million, six hundred eleven thousand, nine hundred eighty".