2131231181 has 2 divisors, whose sum is σ = 2131231182. Its totient is φ = 2131231180.

The previous prime is 2131231171. The next prime is 2131231187. The reversal of 2131231181 is 1811321312.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1586428900 + 544802281 = 39830^2 + 23341^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-2131231181 is a prime.

It is a super-2 number, since 2×2131231181² = 9084292693733309522, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (2131231187) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1065615590 + 1065615591.

It is an arithmetic number, because the mean of its divisors is an integer number (1065615591).

Almost surely, 2^2131231181 is an apocalyptic number.

It is an amenable number.

2131231181 is a deficient number, since it is larger than the sum of its proper divisors (1).

2131231181 is an equidigital number, since it uses as much as digits as its factorization.

2131231181 is an evil number, because the sum of its binary digits is even.

The product of its digits is 288, while the sum is 23.

The square root of 2131231181 is about 46165.2594599012. The cubic root of 2131231181 is about 1286.8962059794.

Adding to 2131231181 its reverse (1811321312), we get a palindrome (3942552493).

The spelling of 2131231181 in words is "two billion, one hundred thirty-one million, two hundred thirty-one thousand, one hundred eighty-one".