6665379839981 has 2 divisors, whose sum is σ = 6665379839982. Its totient is φ = 6665379839980.

The previous prime is 6665379839953. The next prime is 6665379840101. The reversal of 6665379839981 is 1899389735666.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 5322641197225 + 1342738642756 = 2307085^2 + 1158766^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-6665379839981 is a prime.

It is a super-2 number, since 2×6665379839981² (a number of 26 digits) contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 6665379839896 and 6665379839905.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (6665379839381) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (29) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 3332689919990 + 3332689919991.

It is an arithmetic number, because the mean of its divisors is an integer number (3332689919991).

Almost surely, 2^{6665379839981} is an apocalyptic number.

It is an amenable number.

6665379839981 is a deficient number, since it is larger than the sum of its proper divisors (1).

6665379839981 is an equidigital number, since it uses as much as digits as its factorization.

6665379839981 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 3174474240, while the sum is 80.

The spelling of 6665379839981 in words is "six trillion, six hundred sixty-five billion, three hundred seventy-nine million, eight hundred thirty-nine thousand, nine hundred eighty-one".