999872120 has 128 divisors (see below), whose sum is σ = 2510101440. Its totient is φ = 356106240.

The previous prime is 999872059. The next prime is 999872129. The reversal of 999872120 is 21278999.

It is a happy number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (999872129) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 2168690 + ... + 2169150.

Almost surely, 2^999872120 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 999872120, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1255050720).

999872120 is an abundant number, since it is smaller than the sum of its proper divisors (1510229320).

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

999872120 is a wasteful number, since it uses less digits than its factorization.

999872120 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 625 (or 621 counting only the distinct ones).

The product of its (nonzero) digits is 163296, while the sum is 47.

The square root of 999872120 is about 31620.7545767017. The cubic root of 999872120 is about 999.9573715162.

The spelling of 999872120 in words is "nine hundred ninety-nine million, eight hundred seventy-two thousand, one hundred twenty".