999998189 has 4 divisors (see below), whose sum is σ = 1000576956. Its totient is φ = 999419424.

The previous prime is 999998183. The next prime is 999998203. The reversal of 999998189 is 981899999.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 981899999 = 151 ⋅6502649.

It can be written as a sum of positive squares in 2 ways, for example, as 593653225 + 406344964 = 24365^2 + 20158^2 .

It is a cyclic number.

It is not a de Polignac number, because 999998189 - 2⁴ = 999998173 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (999998183) 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, 286784 + ... + 290249.

It is an arithmetic number, because the mean of its divisors is an integer number (250144239).

Almost surely, 2^999998189 is an apocalyptic number.

It is an amenable number.

999998189 is a deficient number, since it is larger than the sum of its proper divisors (578767).

999998189 is a wasteful number, since it uses less digits than its factorization.

999998189 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 578766.

The product of its digits is 34012224, while the sum is 71.

The square root of 999998189 is about 31622.7479672466. The cubic root of 999998189 is about 999.9993963330. Note that the first 3 decimals are identical.

It can be divided in two parts, 999 and 998189, that multiplied together give a triangular number (997190811 = T₄₄₆₅₈).

The spelling of 999998189 in words is "nine hundred ninety-nine million, nine hundred ninety-eight thousand, one hundred eighty-nine".