1321231181 has 2 divisors, whose sum is σ = 1321231182. Its totient is φ = 1321231180.

The previous prime is 1321231141. The next prime is 1321231189. The reversal of 1321231181 is 1811321231.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 938441956 + 382789225 = 30634^2 + 19565^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1321231181 is a prime.

It is a super-2 number, since 2×1321231181² = 3491303667293309522, which contains 22 as substring.

It is a Sophie Germain prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1321231189) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 660615590 + 660615591.

It is an arithmetic number, because the mean of its divisors is an integer number (660615591).

Almost surely, 2^1321231181 is an apocalyptic number.

It is an amenable number.

1321231181 is a deficient number, since it is larger than the sum of its proper divisors (1).

1321231181 is an equidigital number, since it uses as much as digits as its factorization.

1321231181 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 1321231181 is about 36348.7438710061. The cubic root of 1321231181 is about 1097.3022544881.

The spelling of 1321231181 in words is "one billion, three hundred twenty-one million, two hundred thirty-one thousand, one hundred eighty-one".