1998539 has 8 divisors (see below), whose sum is σ = 2153472. Its totient is φ = 1849320.

The previous prime is 1998533. The next prime is 1998541. The reversal of 1998539 is 9358991.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1998539 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 1998539.

It is not an unprimeable number, because it can be changed into a prime (1998533) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 689 + ... + 2114.

It is an arithmetic number, because the mean of its divisors is an integer number (269184).

2^1998539 is an apocalyptic number.

1998539 is a deficient number, since it is larger than the sum of its proper divisors (154933).

1998539 is a wasteful number, since it uses less digits than its factorization.

1998539 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2857.

The product of its digits is 87480, while the sum is 44.

The square root of 1998539 is about 1413.6969265016. The cubic root of 1998539 is about 125.9614184385.

The spelling of 1998539 in words is "one million, nine hundred ninety-eight thousand, five hundred thirty-nine".