1998390 has 32 divisors (see below), whose sum is σ = 4963680. Its totient is φ = 514304.

The previous prime is 1998379. The next prime is 1998397. The reversal of 1998390 is 938991.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1998397) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 279 + ... + 2018.

It is an arithmetic number, because the mean of its divisors is an integer number (155115).

2^1998390 is an apocalyptic number.

1998390 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

1998390 is an abundant number, since it is smaller than the sum of its proper divisors (2965290).

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

1998390 is a wasteful number, since it uses less digits than its factorization.

1998390 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2336.

The product of its (nonzero) digits is 17496, while the sum is 39.

The square root of 1998390 is about 1413.6442268124. The cubic root of 1998390 is about 125.9582880321.

The spelling of 1998390 in words is "one million, nine hundred ninety-eight thousand, three hundred ninety".