1998999 has 40 divisors (see below), whose sum is σ = 3310560. Its totient is φ = 1197504.

The previous prime is 1998991. The next prime is 1999007. The reversal of 1998999 is 9998991.

It is an interprime number because it is at equal distance from previous prime (1998991) and next prime (1999007).

It is not a de Polignac number, because 1998999 - 2³ = 1998991 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1998991) by changing a digit.

It is a polite number, since it can be written in 39 ways as a sum of consecutive naturals, for example, 54009 + ... + 54045.

It is an arithmetic number, because the mean of its divisors is an integer number (82764).

2^1998999 is an apocalyptic number.

1998999 is a deficient number, since it is larger than the sum of its proper divisors (1311561).

1998999 is a wasteful number, since it uses less digits than its factorization.

1998999 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 101 (or 92 counting only the distinct ones).

The product of its digits is 472392, while the sum is 54.

The square root of 1998999 is about 1413.8596111354. The cubic root of 1998999 is about 125.9710817989.

The spelling of 1998999 in words is "one million, nine hundred ninety-eight thousand, nine hundred ninety-nine".