231405137 has 2 divisors, whose sum is σ = 231405138. Its totient is φ = 231405136.

The previous prime is 231405133. The next prime is 231405157. The reversal of 231405137 is 731504132.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 212255761 + 19149376 = 14569^2 + 4376^2 .

It is a cyclic number.

It is not a de Polignac number, because 231405137 - 2² = 231405133 is a prime.

It is not a weakly prime, because it can be changed into another prime (231405131) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 115702568 + 115702569.

It is an arithmetic number, because the mean of its divisors is an integer number (115702569).

Almost surely, 2^231405137 is an apocalyptic number.

It is an amenable number.

231405137 is a deficient number, since it is larger than the sum of its proper divisors (1).

231405137 is an equidigital number, since it uses as much as digits as its factorization.

231405137 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 2520, while the sum is 26.

The square root of 231405137 is about 15212.0063436747. The cubic root of 231405137 is about 613.9377410373.

Adding to 231405137 its reverse (731504132), we get a palindrome (962909269).

The spelling of 231405137 in words is "two hundred thirty-one million, four hundred five thousand, one hundred thirty-seven".