991900224 has 336 divisors, whose sum is σ = 3566160000. Its totient is φ = 257015808.

The previous prime is 991900219. The next prime is 991900313. The reversal of 991900224 is 422009199.

It is a tau number, because it is divible by the number of its divisors (336).

It is a Harshad number since it is a multiple of its sum of digits (36).

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 1987527 + ... + 1988025.

Almost surely, 2^991900224 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 991900224, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1783080000).

991900224 is an abundant number, since it is smaller than the sum of its proper divisors (2574259776).

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

991900224 is a wasteful number, since it uses less digits than its factorization.

991900224 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 570 (or 557 counting only the distinct ones).

The product of its (nonzero) digits is 11664, while the sum is 36.

The square root of 991900224 is about 31494.4475106327. The cubic root of 991900224 is about 997.2927520894.

The spelling of 991900224 in words is "nine hundred ninety-one million, nine hundred thousand, two hundred twenty-four".