243842 has 4 divisors (see below), whose sum is σ = 365766. Its totient is φ = 121920.

The previous prime is 243839. The next prime is 243851. The reversal of 243842 is 248342.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 248342 = 2 ⋅124171.

It can be written as a sum of positive squares in only one way, i.e., 185761 + 58081 = 431^2 + 241^2 .

It is an Ulam number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 60959 + ... + 60962.

2²⁴³⁸⁴² is an apocalyptic number.

243842 is a deficient number, since it is larger than the sum of its proper divisors (121924).

243842 is a wasteful number, since it uses less digits than its factorization.

243842 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 121923.

The product of its digits is 1536, while the sum is 23.

The square root of 243842 is about 493.8036046851. The cubic root of 243842 is about 62.4745069364.

The spelling of 243842 in words is "two hundred forty-three thousand, eight hundred forty-two".