991857152 has 320 divisors, whose sum is σ = 2639831040. Its totient is φ = 364953600.

The previous prime is 991857131. The next prime is 991857169. The reversal of 991857152 is 251758199.

It is a happy number.

It is a super-2 number, since 2×991857152² = 1967561219947102208, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 991857097 and 991857106.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 31995377 + ... + 31995407.

It is an arithmetic number, because the mean of its divisors is an integer number (8249472).

Almost surely, 2^991857152 is an apocalyptic number.

991857152 is a gapful number since it is divisible by the number (92) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 991857152, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1319915520).

991857152 is an abundant number, since it is smaller than the sum of its proper divisors (1647973888).

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

991857152 is a wasteful number, since it uses less digits than its factorization.

991857152 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 115 (or 99 counting only the distinct ones).

The product of its digits is 226800, while the sum is 47.

The square root of 991857152 is about 31493.7637001359. The cubic root of 991857152 is about 997.2783164926.

The spelling of 991857152 in words is "nine hundred ninety-one million, eight hundred fifty-seven thousand, one hundred fifty-two".