91640556 has 144 divisors (see below), whose sum is σ = 280809984. Its totient is φ = 24634368.

The previous prime is 91640543. The next prime is 91640561. The reversal of 91640556 is 65504619.

91640556 is a `hidden beast` number, since 9 + 1 + 640 + 5 + 5 + 6 = 666.

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

It is a self number, because there is not a number n which added to its sum of digits gives 91640556.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 562131 + ... + 562293.

Almost surely, 2^91640556 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 91640556, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (140404992).

91640556 is an abundant number, since it is smaller than the sum of its proper divisors (189169428).

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

91640556 is a wasteful number, since it uses less digits than its factorization.

91640556 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 300 (or 295 counting only the distinct ones).

The product of its (nonzero) digits is 32400, while the sum is 36.

The square root of 91640556 is about 9572.9073953528. The cubic root of 91640556 is about 450.8470563969.

The spelling of 91640556 in words is "ninety-one million, six hundred forty thousand, five hundred fifty-six".