231871511 has 2 divisors, whose sum is σ = 231871512. Its totient is φ = 231871510.

The previous prime is 231871477. The next prime is 231871513. The reversal of 231871511 is 115178132.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 231871511 - 2⁶ = 231871447 is a prime.

It is a super-2 number, since 2×231871511² = 107528795226846242, which contains 22 as substring.

Together with 231871513, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (231871513) 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, 115935755 + 115935756.

It is an arithmetic number, because the mean of its divisors is an integer number (115935756).

Almost surely, 2^231871511 is an apocalyptic number.

231871511 is a deficient number, since it is larger than the sum of its proper divisors (1).

231871511 is an equidigital number, since it uses as much as digits as its factorization.

231871511 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1680, while the sum is 29.

The square root of 231871511 is about 15227.3277695070. The cubic root of 231871511 is about 614.3499077189.

The spelling of 231871511 in words is "two hundred thirty-one million, eight hundred seventy-one thousand, five hundred eleven".