991951912 has 64 divisors (see below), whose sum is σ = 2235340800. Its totient is φ = 403465920.

The previous prime is 991951901. The next prime is 991951957. The reversal of 991951912 is 219159199.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (46).

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 165789 + ... + 171667.

It is an arithmetic number, because the mean of its divisors is an integer number (34927200).

Almost surely, 2^991951912 is an apocalyptic number.

991951912 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 991951912, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1117670400).

991951912 is an abundant number, since it is smaller than the sum of its proper divisors (1243388888).

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

991951912 is a wasteful number, since it uses less digits than its factorization.

991951912 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6046 (or 6042 counting only the distinct ones).

The product of its digits is 65610, while the sum is 46.

The square root of 991951912 is about 31495.2680890320. The cubic root of 991951912 is about 997.3100747902.

The spelling of 991951912 in words is "nine hundred ninety-one million, nine hundred fifty-one thousand, nine hundred twelve".