991253920 has 24 divisors (see below), whose sum is σ = 2341837764. Its totient is φ = 396501504.

The previous prime is 991253917. The next prime is 991253953. The reversal of 991253920 is 29352199.

It can be written as a sum of positive squares in 2 ways, for example, as 991242256 + 11664 = 31484^2 + 108^2 .

It is a Harshad number since it is a multiple of its sum of digits (40).

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3097509 + ... + 3097828.

Almost surely, 2^991253920 is an apocalyptic number.

It is an amenable number.

991253920 is an abundant number, since it is smaller than the sum of its proper divisors (1350583844).

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

991253920 is a wasteful number, since it uses less digits than its factorization.

991253920 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6195352 (or 6195344 counting only the distinct ones).

The product of its (nonzero) digits is 43740, while the sum is 40.

The square root of 991253920 is about 31484.1852364008. The cubic root of 991253920 is about 997.0760991361.

The spelling of 991253920 in words is "nine hundred ninety-one million, two hundred fifty-three thousand, nine hundred twenty".