243181 has 4 divisors (see below), whose sum is σ = 256000. Its totient is φ = 230364.

The previous prime is 243167. The next prime is 243197. The reversal of 243181 is 181342.

243181 = 104² + 105² + ... + 122².

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.

It is a cyclic number.

It is not a de Polignac number, because 243181 - 2⁵ = 243149 is a prime.

It is a super-2 number, since 2×243181² = 118273997522, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (19), and also a Moran number because the ratio is a prime number: 12799 = 243181 / (2 + 4 + 3 + 1 + 8 + 1).

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (243101) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 6381 + ... + 6418.

It is an arithmetic number, because the mean of its divisors is an integer number (64000).

2²⁴³¹⁸¹ is an apocalyptic number.

It is an amenable number.

243181 is a deficient number, since it is larger than the sum of its proper divisors (12819).

243181 is a wasteful number, since it uses less digits than its factorization.

243181 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 12818.

The product of its digits is 192, while the sum is 19.

The square root of 243181 is about 493.1338560675. The cubic root of 243181 is about 62.4180044748.

It can be divided in two parts, 243 and 181, that added together give a palindrome (424).

The spelling of 243181 in words is "two hundred forty-three thousand, one hundred eighty-one".