999870816 has 96 divisors (see below), whose sum is σ = 3103107840. Its totient is φ = 275821056.

The previous prime is 999870769. The next prime is 999870829. The reversal of 999870816 is 618078999.

It is a tau number, because it is divible by the number of its divisors (96).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 6166 + ... + 45141.

It is an arithmetic number, because the mean of its divisors is an integer number (32324040).

Almost surely, 2^999870816 is an apocalyptic number.

999870816 is a gapful number since it is divisible by the number (96) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 999870816, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1551553920).

999870816 is an abundant number, since it is smaller than the sum of its proper divisors (2103237024).

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

999870816 is a wasteful number, since it uses less digits than its factorization.

999870816 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 51356 (or 51348 counting only the distinct ones).

The product of its (nonzero) digits is 1959552, while the sum is 57.

The square root of 999870816 is about 31620.7339573262. The cubic root of 999870816 is about 999.9569368123.

The spelling of 999870816 in words is "nine hundred ninety-nine million, eight hundred seventy thousand, eight hundred sixteen".