231781998361 has 2 divisors, whose sum is σ = 231781998362. Its totient is φ = 231781998360.

The previous prime is 231781998323. The next prime is 231781998401. The reversal of 231781998361 is 163899187132.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 187797422736 + 43984575625 = 433356^2 + 209725^2 .

It is a cyclic number.

It is not a de Polignac number, because 231781998361 - 2²⁵ = 231748443929 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 231781998296 and 231781998305.

It is not a weakly prime, because it can be changed into another prime (231781998661) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 115890999180 + 115890999181.

It is an arithmetic number, because the mean of its divisors is an integer number (115890999181).

Almost surely, 2^231781998361 is an apocalyptic number.

It is an amenable number.

231781998361 is a deficient number, since it is larger than the sum of its proper divisors (1).

231781998361 is an equidigital number, since it uses as much as digits as its factorization.

231781998361 is an evil number, because the sum of its binary digits is even.

The product of its digits is 3919104, while the sum is 58.

The spelling of 231781998361 in words is "two hundred thirty-one billion, seven hundred eighty-one million, nine hundred ninety-eight thousand, three hundred sixty-one".