231998842099781 has 2 divisors, whose sum is σ = 231998842099782. Its totient is φ = 231998842099780.

The previous prime is 231998842099763. The next prime is 231998842099811. The reversal of 231998842099781 is 187990248899132.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 144834846520225 + 87163995579556 = 12034735^2 + 9336166^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-231998842099781 is a prime.

It is a super-2 number, since 2×231998842099781² (a number of 30 digits) contains 22 as substring.

It is a Sophie Germain prime.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 231998842099696 and 231998842099705.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (231998842099181) 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, 115999421049890 + 115999421049891.

It is an arithmetic number, because the mean of its divisors is an integer number (115999421049891).

Almost surely, 2^{231998842099781} is an apocalyptic number.

It is an amenable number.

231998842099781 is a deficient number, since it is larger than the sum of its proper divisors (1).

231998842099781 is an equidigital number, since it uses as much as digits as its factorization.

231998842099781 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1128701952, while the sum is 80.

The spelling of 231998842099781 in words is "two hundred thirty-one trillion, nine hundred ninety-eight billion, eight hundred forty-two million, ninety-nine thousand, seven hundred eighty-one".