243505131 has 4 divisors (see below), whose sum is σ = 324673512. Its totient is φ = 162336752.

The previous prime is 243505099. The next prime is 243505147. The reversal of 243505131 is 131505342.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 243505131 - 2⁵ = 243505099 is a prime.

It is a super-2 number, since 2×243505131² = 118589497646654322, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (243505181) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 40584186 + ... + 40584191.

It is an arithmetic number, because the mean of its divisors is an integer number (81168378).

Almost surely, 2^243505131 is an apocalyptic number.

243505131 is a deficient number, since it is larger than the sum of its proper divisors (81168381).

243505131 is an equidigital number, since it uses as much as digits as its factorization.

243505131 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 81168380.

The product of its (nonzero) digits is 1800, while the sum is 24.

The square root of 243505131 is about 15604.6509413059. The cubic root of 243505131 is about 624.4572405827.

The spelling of 243505131 in words is "two hundred forty-three million, five hundred five thousand, one hundred thirty-one".