991567872 has 112 divisors (see below), whose sum is σ = 2938454880. Its totient is φ = 330448896.

The previous prime is 991567861. The next prime is 991567873. The reversal of 991567872 is 278765199.

991567872 is a `hidden beast` number, since 9 + 9 + 1 + 567 + 8 + 72 = 666.

It is a Smith number, since the sum of its digits (54) coincides with the sum of the digits of its prime factors.

It is a Harshad number since it is a multiple of its sum of digits (54).

It is not an unprimeable number, because it can be changed into a prime (991567873) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 218943 + ... + 223425.

Almost surely, 2^991567872 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 991567872, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1469227440).

991567872 is an abundant number, since it is smaller than the sum of its proper divisors (1946887008).

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

991567872 is an equidigital number, since it uses as much as digits as its factorization.

991567872 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4518 (or 4488 counting only the distinct ones).

The product of its digits is 1905120, while the sum is 54.

The square root of 991567872 is about 31489.1707099441. The cubic root of 991567872 is about 997.1813533623.

The spelling of 991567872 in words is "nine hundred ninety-one million, five hundred sixty-seven thousand, eight hundred seventy-two".