231321319981 has 2 divisors, whose sum is σ = 231321319982. Its totient is φ = 231321319980.

The previous prime is 231321319963. The next prime is 231321319987. The reversal of 231321319981 is 189913123132.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 215194859881 + 16126460100 = 463891^2 + 126990^2 .

It is a cyclic number.

It is not a de Polignac number, because 231321319981 - 2²⁵ = 231287765549 is a prime.

It is a super-2 number, since 2×231321319981² (a number of 24 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (231321319987) 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, 115660659990 + 115660659991.

It is an arithmetic number, because the mean of its divisors is an integer number (115660659991).

Almost surely, 2^231321319981 is an apocalyptic number.

It is an amenable number.

231321319981 is a deficient number, since it is larger than the sum of its proper divisors (1).

231321319981 is an equidigital number, since it uses as much as digits as its factorization.

231321319981 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 69984, while the sum is 43.

The spelling of 231321319981 in words is "two hundred thirty-one billion, three hundred twenty-one million, three hundred nineteen thousand, nine hundred eighty-one".