1998864 has 80 divisors (see below), whose sum is σ = 6567040. Its totient is φ = 570240.

The previous prime is 1998839. The next prime is 1998881. The reversal of 1998864 is 4688991.

It is a nude number because it is divisible by every one of its digits.

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, 2694 + ... + 3354.

It is an arithmetic number, because the mean of its divisors is an integer number (82088).

2^1998864 is an apocalyptic number.

1998864 is a gapful number since it is divisible by the number (14) 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 1998864, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (3283520).

1998864 is an abundant number, since it is smaller than the sum of its proper divisors (4568176).

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

1998864 is a wasteful number, since it uses less digits than its factorization.

1998864 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 685 (or 673 counting only the distinct ones).

The product of its digits is 124416, while the sum is 45.

The square root of 1998864 is about 1413.8118686728. The cubic root of 1998864 is about 125.9682459664.

The spelling of 1998864 in words is "one million, nine hundred ninety-eight thousand, eight hundred sixty-four".