231221686957 has 2 divisors, whose sum is σ = 231221686958. Its totient is φ = 231221686956.

The previous prime is 231221686921. The next prime is 231221686973. The reversal of 231221686957 is 759686122132.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 174378067396 + 56843619561 = 417586^2 + 238419^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-231221686957 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (231221686357) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 115610843478 + 115610843479.

It is an arithmetic number, because the mean of its divisors is an integer number (115610843479).

Almost surely, 2^231221686957 is an apocalyptic number.

It is an amenable number.

231221686957 is a deficient number, since it is larger than the sum of its proper divisors (1).

231221686957 is an equidigital number, since it uses as much as digits as its factorization.

231221686957 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 2177280, while the sum is 52.

The spelling of 231221686957 in words is "two hundred thirty-one billion, two hundred twenty-one million, six hundred eighty-six thousand, nine hundred fifty-seven".