991235120 has 40 divisors (see below), whose sum is σ = 2333808960. Its totient is φ = 391472640.

The previous prime is 991235081. The next prime is 991235131. The reversal of 991235120 is 21532199.

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, 72101 + ... + 84740.

It is an arithmetic number, because the mean of its divisors is an integer number (58345224).

Almost surely, 2^991235120 is an apocalyptic number.

It is an amenable number.

991235120 is an abundant number, since it is smaller than the sum of its proper divisors (1342573840).

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

991235120 is a wasteful number, since it uses less digits than its factorization.

991235120 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 156933 (or 156927 counting only the distinct ones).

The product of its (nonzero) digits is 4860, while the sum is 32.

The square root of 991235120 is about 31483.8866723916. The cubic root of 991235120 is about 997.0697956220.

The spelling of 991235120 in words is "nine hundred ninety-one million, two hundred thirty-five thousand, one hundred twenty".