1998931 has 4 divisors (see below), whose sum is σ = 2180664. Its totient is φ = 1817200.

The previous prime is 1998923. The next prime is 1998943. The reversal of 1998931 is 1398991.

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

It is not a de Polignac number, because 1998931 - 2³ = 1998923 is a prime.

It is a super-2 number, since 2×1998931² = 7991450285522, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1998961) 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, 90850 + ... + 90871.

It is an arithmetic number, because the mean of its divisors is an integer number (545166).

2^1998931 is an apocalyptic number.

1998931 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

1998931 is a deficient number, since it is larger than the sum of its proper divisors (181733).

1998931 is a wasteful number, since it uses less digits than its factorization.

1998931 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 181732.

The product of its digits is 17496, while the sum is 40.

The square root of 1998931 is about 1413.8355632817. The cubic root of 1998931 is about 125.9696533955.

The spelling of 1998931 in words is "one million, nine hundred ninety-eight thousand, nine hundred thirty-one".