231321491 has 2 divisors, whose sum is σ = 231321492. Its totient is φ = 231321490.

The previous prime is 231321469. The next prime is 231321539. The reversal of 231321491 is 194123132.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-231321491 is a prime.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 231321491.

It is not a weakly prime, because it can be changed into another prime (231321191) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 115660745 + 115660746.

It is an arithmetic number, because the mean of its divisors is an integer number (115660746).

Almost surely, 2^231321491 is an apocalyptic number.

231321491 is a deficient number, since it is larger than the sum of its proper divisors (1).

231321491 is an equidigital number, since it uses as much as digits as its factorization.

231321491 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1296, while the sum is 26.

The square root of 231321491 is about 15209.2567537010. The cubic root of 231321491 is about 613.8637587772.

The spelling of 231321491 in words is "two hundred thirty-one million, three hundred twenty-one thousand, four hundred ninety-one".