1998090 has 36 divisors (see below), whose sum is σ = 5230134. Its totient is φ = 529248.

The previous prime is 1998089. The next prime is 1998107. The reversal of 1998090 is 908991.

It can be written as a sum of positive squares in 3 ways, for example, as 772641 + 1225449 = 879^2 + 1107^2 .

It is an unprimeable number.

It is a polite number, since it can be written in 17 ways as a sum of consecutive naturals, for example, 13336 + ... + 13484.

2^1998090 is an apocalyptic number.

1998090 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is a practical number, because each smaller number is the sum of distinct divisors of 1998090, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2615067).

1998090 is an abundant number, since it is smaller than the sum of its proper divisors (3232044).

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

1998090 is a wasteful number, since it uses less digits than its factorization.

1998090 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 311 (or 159 counting only the distinct ones).

The product of its (nonzero) digits is 5832, while the sum is 36.

The square root of 1998090 is about 1413.5381140953. The cubic root of 1998090 is about 125.9519847284.

The spelling of 1998090 in words is "one million, nine hundred ninety-eight thousand, ninety".