243531 has 6 divisors (see below), whose sum is σ = 351780. Its totient is φ = 162348.

The previous prime is 243527. The next prime is 243533. The reversal of 243531 is 135342.

It is not a de Polignac number, because 243531 - 2² = 243527 is a prime.

It is a super-2 number, since 2×243531² = 118614695922, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (243533) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 13521 + ... + 13538.

It is an arithmetic number, because the mean of its divisors is an integer number (58630).

2²⁴³⁵³¹ is an apocalyptic number.

243531 is a deficient number, since it is larger than the sum of its proper divisors (108249).

243531 is a wasteful number, since it uses less digits than its factorization.

243531 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 27065 (or 27062 counting only the distinct ones).

The product of its digits is 360, while the sum is 18.

The square root of 243531 is about 493.4886016921. The cubic root of 243531 is about 62.4479353070.

Adding to 243531 its reverse (135342), we get a palindrome (378873).

The spelling of 243531 in words is "two hundred forty-three thousand, five hundred thirty-one".