991132800 has 480 divisors, whose sum is σ = 3896975280. Its totient is φ = 221276160.

The previous prime is 991132783. The next prime is 991132823. The reversal of 991132800 is 8231199.

It is a tau number, because it is divible by the number of its divisors (480).

It is an unprimeable number.

It is a polite number, since it can be written in 59 ways as a sum of consecutive naturals, for example, 23049579 + ... + 23049621.

Almost surely, 2^991132800 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 991132800, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1948487640).

991132800 is an abundant number, since it is smaller than the sum of its proper divisors (2905842480).

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

991132800 is an equidigital number, since it uses as much as digits as its factorization.

991132800 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 98 (or 60 counting only the distinct ones).

The product of its (nonzero) digits is 3888, while the sum is 33.

The square root of 991132800 is about 31482.2616722497. The cubic root of 991132800 is about 997.0354870138.

Adding to 991132800 its reverse (8231199), we get a palindrome (999363999).

The spelling of 991132800 in words is "nine hundred ninety-one million, one hundred thirty-two thousand, eight hundred".