991974208 has 56 divisors (see below), whose sum is σ = 2151546624. Its totient is φ = 451737600.

The previous prime is 991974187. The next prime is 991974223. The reversal of 991974208 is 802479199.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 19023 + ... + 48433.

Almost surely, 2^991974208 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 991974208, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1075773312).

991974208 is an abundant number, since it is smaller than the sum of its proper divisors (1159572416).

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

991974208 is a wasteful number, since it uses less digits than its factorization.

991974208 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 29471 (or 29461 counting only the distinct ones).

The product of its (nonzero) digits is 326592, while the sum is 49.

The square root of 991974208 is about 31495.6220449763. The cubic root of 991974208 is about 997.3175468792.

The spelling of 991974208 in words is "nine hundred ninety-one million, nine hundred seventy-four thousand, two hundred eight".