243401531 has 2 divisors, whose sum is σ = 243401532. Its totient is φ = 243401530.

The previous prime is 243401513. The next prime is 243401549. The reversal of 243401531 is 135104342.

Together with previous prime (243401513) it forms an Ormiston pair, because they use the same digits, order apart.

It is a balanced prime because it is at equal distance from previous prime (243401513) and next prime (243401549).

It is a cyclic number.

It is not a de Polignac number, because 243401531 - 2²⁶ = 176292667 is a prime.

It is a super-2 number, since 2×243401531² = 118488610586287922, which contains 22 as substring.

It is a Sophie Germain prime.

It is a Chen prime.

It is a junction number, because it is equal to n+sod(n) for n = 243401497 and 243401506.

It is not a weakly prime, because it can be changed into another prime (243401551) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 121700765 + 121700766.

It is an arithmetic number, because the mean of its divisors is an integer number (121700766).

Almost surely, 2^243401531 is an apocalyptic number.

243401531 is a deficient number, since it is larger than the sum of its proper divisors (1).

243401531 is an equidigital number, since it uses as much as digits as its factorization.

243401531 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1440, while the sum is 23.

The square root of 243401531 is about 15601.3310650085. The cubic root of 243401531 is about 624.3686689418.

Adding to 243401531 its reverse (135104342), we get a palindrome (378505873).

The spelling of 243401531 in words is "two hundred forty-three million, four hundred one thousand, five hundred thirty-one".