999900972 has 144 divisors (see below), whose sum is σ = 2944614400. Its totient is φ = 280215936.

The previous prime is 999900961. The next prime is 999900991. The reversal of 999900972 is 279009999.

It is a hoax number, since the sum of its digits (54) coincides with the sum of the digits of its distinct prime factors.

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, 5024529 + ... + 5024727.

Almost surely, 2^999900972 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 999900972, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1472307200).

999900972 is an abundant number, since it is smaller than the sum of its proper divisors (1944713428).

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

999900972 is a wasteful number, since it uses less digits than its factorization.

999900972 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 500 (or 495 counting only the distinct ones).

The product of its (nonzero) digits is 826686, while the sum is 54.

The square root of 999900972 is about 31621.2107927574. The cubic root of 999900972 is about 999.9669895770.

The spelling of 999900972 in words is "nine hundred ninety-nine million, nine hundred thousand, nine hundred seventy-two".