231981181 has 2 divisors, whose sum is σ = 231981182. Its totient is φ = 231981180.

The previous prime is 231981163. The next prime is 231981187. The reversal of 231981181 is 181189132.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 205664281 + 26316900 = 14341^2 + 5130^2 .

It is a cyclic number.

It is not a de Polignac number, because 231981181 - 2¹⁹ = 231456893 is a prime.

It is a super-2 number, since 2×231981181² = 107630536676309522, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (231981187) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 115990590 + 115990591.

It is an arithmetic number, because the mean of its divisors is an integer number (115990591).

Almost surely, 2^231981181 is an apocalyptic number.

It is an amenable number.

231981181 is a deficient number, since it is larger than the sum of its proper divisors (1).

231981181 is an equidigital number, since it uses as much as digits as its factorization.

231981181 is an evil number, because the sum of its binary digits is even.

The product of its digits is 3456, while the sum is 34.

The square root of 231981181 is about 15230.9284352596. The cubic root of 231981181 is about 614.4467503401.

The spelling of 231981181 in words is "two hundred thirty-one million, nine hundred eighty-one thousand, one hundred eighty-one".