243421531 has 2 divisors, whose sum is σ = 243421532. Its totient is φ = 243421530.

The previous prime is 243421511. The next prime is 243421543. The reversal of 243421531 is 135124342.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 243421531 - 2¹⁵ = 243388763 is a prime.

It is a super-2 number, since 2×243421531² = 118508083508767922, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 243421496 and 243421505.

It is not a weakly prime, because it can be changed into another prime (243421511) 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 as a sum of consecutive naturals, namely, 121710765 + 121710766.

It is an arithmetic number, because the mean of its divisors is an integer number (121710766).

Almost surely, 2^243421531 is an apocalyptic number.

243421531 is a deficient number, since it is larger than the sum of its proper divisors (1).

243421531 is an equidigital number, since it uses as much as digits as its factorization.

243421531 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 2880, while the sum is 25.

The square root of 243421531 is about 15601.9720227925. The cubic root of 243421531 is about 624.3857696715.

Adding to 243421531 its reverse (135124342), we get a palindrome (378545873).

The spelling of 243421531 in words is "two hundred forty-three million, four hundred twenty-one thousand, five hundred thirty-one".