999919872 has 324 divisors, whose sum is σ = 3557804796. Its totient is φ = 268369920.

The previous prime is 999919847. The next prime is 999919901. The reversal of 999919872 is 278919999.

It can be written as a sum of positive squares in 2 ways, for example, as 537497856 + 462422016 = 23184^2 + 21504^2 .

It is a Harshad number since it is a multiple of its sum of digits (63).

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

It is an unprimeable number.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 1918972 + ... + 1919492.

It is an arithmetic number, because the mean of its divisors is an integer number (10980879).

Almost surely, 2^999919872 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 999919872, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1778902398).

999919872 is an abundant number, since it is smaller than the sum of its proper divisors (2557884924).

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

999919872 is a wasteful number, since it uses less digits than its factorization.

999919872 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 574 (or 550 counting only the distinct ones).

The product of its digits is 6613488, while the sum is 63.

The square root of 999919872 is about 31621.5096413818. The cubic root of 999919872 is about 999.9732899532.

The spelling of 999919872 in words is "nine hundred ninety-nine million, nine hundred nineteen thousand, eight hundred seventy-two".