1998340 has 24 divisors (see below), whose sum is σ = 4300632. Its totient is φ = 779520.

The previous prime is 1998331. The next prime is 1998341. The reversal of 1998340 is 438991.

It can be written as a sum of positive squares in 4 ways, for example, as 186624 + 1811716 = 432^2 + 1346^2 .

It is a junction number, because it is equal to n+sod(n) for n = 1998296 and 1998305.

It is not an unprimeable number, because it can be changed into a prime (1998341) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 399 + ... + 2038.

It is an arithmetic number, because the mean of its divisors is an integer number (179193).

2^1998340 is an apocalyptic number.

1998340 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1998340 is an abundant number, since it is smaller than the sum of its proper divisors (2302292).

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

1998340 is a wasteful number, since it uses less digits than its factorization.

1998340 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2487 (or 2485 counting only the distinct ones).

The product of its (nonzero) digits is 7776, while the sum is 34.

The square root of 1998340 is about 1413.6265419127. The cubic root of 1998340 is about 125.9572375253.

The spelling of 1998340 in words is "one million, nine hundred ninety-eight thousand, three hundred forty".