1998889 has 4 divisors (see below), whose sum is σ = 2023056. Its totient is φ = 1974724.

The previous prime is 1998881. The next prime is 1998917. The reversal of 1998889 is 9888991.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 9888991 = 7 ⋅1412713.

It is a cyclic number.

It is not a de Polignac number, because 1998889 - 2³ = 1998881 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1998881) 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, 11959 + ... + 12124.

It is an arithmetic number, because the mean of its divisors is an integer number (505764).

2^1998889 is an apocalyptic number.

It is an amenable number.

1998889 is a deficient number, since it is larger than the sum of its proper divisors (24167).

1998889 is an equidigital number, since it uses as much as digits as its factorization.

1998889 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 24166.

The product of its digits is 373248, while the sum is 52.

The square root of 1998889 is about 1413.8207099912. The cubic root of 1998889 is about 125.9687711302.

It can be divided in two parts, 19 and 98889, that multiplied together give a triangular number (1878891 = T₁₉₃₈).

The spelling of 1998889 in words is "one million, nine hundred ninety-eight thousand, eight hundred eighty-nine".