6666337879781 has 2 divisors, whose sum is σ = 6666337879782. Its totient is φ = 6666337879780.

The previous prime is 6666337879711. The next prime is 6666337879793. The reversal of 6666337879781 is 1879787336666.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 6605974303681 + 60363576100 = 2570209^2 + 245690^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-6666337879781 is a prime.

It is a super-2 number, since 2×6666337879781² (a number of 26 digits) 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 (6666337879711) 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, 3333168939890 + 3333168939891.

It is an arithmetic number, because the mean of its divisors is an integer number (3333168939891).

Almost surely, 2^{6666337879781} is an apocalyptic number.

It is an amenable number.

6666337879781 is a deficient number, since it is larger than the sum of its proper divisors (1).

6666337879781 is an equidigital number, since it uses as much as digits as its factorization.

6666337879781 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 2304433152, while the sum is 77.

The spelling of 6666337879781 in words is "six trillion, six hundred sixty-six billion, three hundred thirty-seven million, eight hundred seventy-nine thousand, seven hundred eighty-one".