243913 has 4 divisors (see below), whose sum is σ = 245700. Its totient is φ = 242128.

The previous prime is 243911. The next prime is 243917. The reversal of 243913 is 319342.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 319342 = 2 ⋅159671.

It can be written as a sum of positive squares in 2 ways, for example, as 16384 + 227529 = 128^2 + 477^2 .

It is a cyclic number.

It is not a de Polignac number, because 243913 - 2¹ = 243911 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (243911) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 670 + ... + 967.

It is an arithmetic number, because the mean of its divisors is an integer number (61425).

2²⁴³⁹¹³ is an apocalyptic number.

It is an amenable number.

243913 is a deficient number, since it is larger than the sum of its proper divisors (1787).

243913 is a wasteful number, since it uses less digits than its factorization.

243913 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1786.

The product of its digits is 648, while the sum is 22.

The square root of 243913 is about 493.8754903819. The cubic root of 243913 is about 62.4805699602.

It can be divided in two parts, 243 and 913, that added together give a square (1156 = 34²).

The spelling of 243913 in words is "two hundred forty-three thousand, nine hundred thirteen".