991084560 has 40 divisors (see below), whose sum is σ = 3072362880. Its totient is φ = 264289152.

The previous prime is 991084531. The next prime is 991084579. The reversal of 991084560 is 65480199.

It is a tau number, because it is divible by the number of its divisors (40).

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2064520 + ... + 2064999.

It is an arithmetic number, because the mean of its divisors is an integer number (76809072).

Almost surely, 2^991084560 is an apocalyptic number.

It is an amenable number.

991084560 is an abundant number, since it is smaller than the sum of its proper divisors (2081278320).

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

991084560 is a wasteful number, since it uses less digits than its factorization.

991084560 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4129535 (or 4129529 counting only the distinct ones).

The product of its (nonzero) digits is 77760, while the sum is 42.

The square root of 991084560 is about 31481.4955172082. The cubic root of 991084560 is about 997.0193109870.

The spelling of 991084560 in words is "nine hundred ninety-one million, eighty-four thousand, five hundred sixty".