999989980 has 144 divisors (see below), whose sum is σ = 2477502720. Its totient is φ = 337582080.

The previous prime is 999989957. The next prime is 999989981. The reversal of 999989980 is 89989999.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (999989981) 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 47 ways as a sum of consecutive naturals, for example, 4484149 + ... + 4484371.

It is an arithmetic number, because the mean of its divisors is an integer number (17204880).

Almost surely, 2^999989980 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 999989980, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1238751360).

999989980 is an abundant number, since it is smaller than the sum of its proper divisors (1477512740).

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

999989980 is a wasteful number, since it uses less digits than its factorization.

999989980 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 380 (or 367 counting only the distinct ones).

The product of its (nonzero) digits is 34012224, while the sum is 70.

The square root of 999989980 is about 31622.6181711761. The cubic root of 999989980 is about 999.9966599888.

The spelling of 999989980 in words is "nine hundred ninety-nine million, nine hundred eighty-nine thousand, nine hundred eighty".