198639 has 16 divisors (see below), whose sum is σ = 336640. Its totient is φ = 113400.

The previous prime is 198637. The next prime is 198641. The reversal of 198639 is 936891.

198639 is a `hidden beast` number, since 19 + 8 + 639 = 666.

It is an interprime number because it is at equal distance from previous prime (198637) and next prime (198641).

It is not a de Polignac number, because 198639 - 2¹ = 198637 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 (198637) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 337 + ... + 714.

It is an arithmetic number, because the mean of its divisors is an integer number (21040).

2¹⁹⁸⁶³⁹ is an apocalyptic number.

198639 is a deficient number, since it is larger than the sum of its proper divisors (138001).

198639 is a wasteful number, since it uses less digits than its factorization.

198639 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1067 (or 1061 counting only the distinct ones).

The product of its digits is 11664, while the sum is 36.

The square root of 198639 is about 445.6893536983. The cubic root of 198639 is about 58.3473997824.

It can be divided in two parts, 1986 and 39, that added together give a square (2025 = 45²).

The spelling of 198639 in words is "one hundred ninety-eight thousand, six hundred thirty-nine".