198531 has 24 divisors (see below), whose sum is σ = 320320. Its totient is φ = 122472.

The previous prime is 198529. The next prime is 198533. The reversal of 198531 is 135891.

198531 is nontrivially palindromic in base 2.

It is an interprime number because it is at equal distance from previous prime (198529) and next prime (198533).

It is not a de Polignac number, because 198531 - 2¹ = 198529 is a prime.

It is a super-2 number, since 2×198531² = 78829115922, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a Duffinian number.

It is a zygodrome in base 2.

It is a junction number, because it is equal to n+sod(n) for n = 198495 and 198504.

It is not an unprimeable number, because it can be changed into a prime (198533) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 4596 + ... + 4638.

2¹⁹⁸⁵³¹ is an apocalyptic number.

198531 is a deficient number, since it is larger than the sum of its proper divisors (121789).

198531 is an equidigital number, since it uses as much as digits as its factorization.

198531 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 77 (or 65 counting only the distinct ones).

The product of its digits is 1080, while the sum is 27.

The square root of 198531 is about 445.5681766015. The cubic root of 198531 is about 58.3368233740.

It can be divided in two parts, 1985 and 31, that added together give a triangular number (2016 = T₆₃).

The spelling of 198531 in words is "one hundred ninety-eight thousand, five hundred thirty-one".