1323431981 has 2 divisors, whose sum is σ = 1323431982. Its totient is φ = 1323431980.

The previous prime is 1323431959. The next prime is 1323432001. The reversal of 1323431981 is 1891343231.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1247149225 + 76282756 = 35315^2 + 8734^2 .

It is a cyclic number.

It is not a de Polignac number, because 1323431981 - 2¹⁰ = 1323430957 is a prime.

It is a super-2 number, since 2×1323431981² = 3502944416667168722, 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 (1323431911) 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, 661715990 + 661715991.

It is an arithmetic number, because the mean of its divisors is an integer number (661715991).

Almost surely, 2^1323431981 is an apocalyptic number.

It is an amenable number.

1323431981 is a deficient number, since it is larger than the sum of its proper divisors (1).

1323431981 is an equidigital number, since it uses as much as digits as its factorization.

1323431981 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 15552, while the sum is 35.

The square root of 1323431981 is about 36379.0046730253. The cubic root of 1323431981 is about 1097.9111822831.

The spelling of 1323431981 in words is "one billion, three hundred twenty-three million, four hundred thirty-one thousand, nine hundred eighty-one".