12399343981 has 2 divisors, whose sum is σ = 12399343982. Its totient is φ = 12399343980.

The previous prime is 12399343951. The next prime is 12399344017. The reversal of 12399343981 is 18934399321.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 10102059081 + 2297284900 = 100509^2 + 47930^2 .

It is a cyclic number.

It is not a de Polignac number, because 12399343981 - 2²³ = 12390955373 is a prime.

It is a super-2 number, since 2×12399343981² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (12399343951) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 6199671990 + 6199671991.

It is an arithmetic number, because the mean of its divisors is an integer number (6199671991).

Almost surely, 2^12399343981 is an apocalyptic number.

It is an amenable number.

12399343981 is a deficient number, since it is larger than the sum of its proper divisors (1).

12399343981 is an equidigital number, since it uses as much as digits as its factorization.

12399343981 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1259712, while the sum is 52.

It can be divided in two parts, 12 and 399343981, that added together give a palindrome (399343993).

The spelling of 12399343981 in words is "twelve billion, three hundred ninety-nine million, three hundred forty-three thousand, nine hundred eighty-one".