1998831 has 4 divisors (see below), whose sum is σ = 2665112. Its totient is φ = 1332552.

The previous prime is 1998827. The next prime is 1998839. The reversal of 1998831 is 1388991.

It is a happy number.

It is a semiprime because it is the product of two primes.

It is not a de Polignac number, because 1998831 - 2² = 1998827 is a prime.

It is a super-2 number, since 2×1998831² = 7990650733122, which contains 22 as substring.

It is a D-number.

It is a Duffinian number.

1998831 is a lucky number.

It is a self number, because there is not a number n which added to its sum of digits gives 1998831.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1998839) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 333136 + ... + 333141.

It is an arithmetic number, because the mean of its divisors is an integer number (666278).

2^1998831 is an apocalyptic number.

1998831 is a deficient number, since it is larger than the sum of its proper divisors (666281).

1998831 is an equidigital number, since it uses as much as digits as its factorization.

1998831 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 666280.

The product of its digits is 15552, while the sum is 39.

The square root of 1998831 is about 1413.8001980478. The cubic root of 1998831 is about 125.9675527435.

The spelling of 1998831 in words is "one million, nine hundred ninety-eight thousand, eight hundred thirty-one".