1998889920 has 448 divisors, whose sum is σ = 7724851200. Its totient is φ = 484392960.

The previous prime is 1998889891. The next prime is 1998889943. The reversal of 1998889920 is 299888991.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 4553061 + ... + 4553499.

Almost surely, 2^1998889920 is an apocalyptic number.

1998889920 is a gapful number since it is divisible by the number (10) 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 1998889920, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (3862425600).

1998889920 is an abundant number, since it is smaller than the sum of its proper divisors (5725961280).

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

1998889920 is a wasteful number, since it uses less digits than its factorization.

1998889920 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 513 (or 497 counting only the distinct ones).

The product of its (nonzero) digits is 6718464, while the sum is 63.

The square root of 1998889920 is about 44708.9467556551. The cubic root of 1998889920 is about 1259.6879045614.

The spelling of 1998889920 in words is "one billion, nine hundred ninety-eight million, eight hundred eighty-nine thousand, nine hundred twenty".