991636992 has 100 divisors (see below), whose sum is σ = 2959899096. Its totient is φ = 330531840.

The previous prime is 991636969. The next prime is 991637041. The reversal of 991636992 is 299636199.

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

It is a nude number because it is divisible by every one of its digits.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 9 ways as a sum of consecutive naturals, for example, 29517 + ... + 53427.

Almost surely, 2^991636992 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 991636992, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1479949548).

991636992 is an abundant number, since it is smaller than the sum of its proper divisors (1968262104).

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

991636992 is an equidigital number, since it uses as much as digits as its factorization.

991636992 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 23941 (or 23916 counting only the distinct ones).

The product of its digits is 1417176, while the sum is 54.

The square root of 991636992 is about 31490.2682109886. The cubic root of 991636992 is about 997.2045232584.

The spelling of 991636992 in words is "nine hundred ninety-one million, six hundred thirty-six thousand, nine hundred ninety-two".