231537281 has 2 divisors, whose sum is σ = 231537282. Its totient is φ = 231537280.

The previous prime is 231537277. The next prime is 231537283. The reversal of 231537281 is 182735132.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 131217025 + 100320256 = 11455^2 + 10016^2 .

It is a cyclic number.

It is not a de Polignac number, because 231537281 - 2² = 231537277 is a prime.

It is a super-2 number, since 2×231537281² = 107219024985745922, which contains 22 as substring.

Together with 231537283, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (231537283) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 115768640 + 115768641.

It is an arithmetic number, because the mean of its divisors is an integer number (115768641).

Almost surely, 2^231537281 is an apocalyptic number.

It is an amenable number.

231537281 is a deficient number, since it is larger than the sum of its proper divisors (1).

231537281 is an equidigital number, since it uses as much as digits as its factorization.

231537281 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 10080, while the sum is 32.

The square root of 231537281 is about 15216.3491350586. The cubic root of 231537281 is about 614.0545819338.

The spelling of 231537281 in words is "two hundred thirty-one million, five hundred thirty-seven thousand, two hundred eighty-one".