991607808 has 88 divisors (see below), whose sum is σ = 2688284160. Its totient is φ = 324874240.

The previous prime is 991607753. The next prime is 991607849. The reversal of 991607808 is 808706199.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (48).

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 7 ways as a sum of consecutive naturals, for example, 178513 + ... + 183983.

Almost surely, 2^991607808 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 991607808, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1344142080).

991607808 is an abundant number, since it is smaller than the sum of its proper divisors (1696676352).

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

991607808 is a wasteful number, since it uses less digits than its factorization.

991607808 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5553 (or 5535 counting only the distinct ones).

The product of its (nonzero) digits is 217728, while the sum is 48.

The square root of 991607808 is about 31489.8048263243. The cubic root of 991607808 is about 997.1947405447.

The spelling of 991607808 in words is "nine hundred ninety-one million, six hundred seven thousand, eight hundred eight".