6661868024381 has 2 divisors, whose sum is σ = 6661868024382. Its totient is φ = 6661868024380.

The previous prime is 6661868024377. The next prime is 6661868024411. The reversal of 6661868024381 is 1834208681666.

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., 3952008817156 + 2709859207225 = 1987966^2 + 1646165^2 .

It is a cyclic number.

It is not a de Polignac number, because 6661868024381 - 2² = 6661868024377 is a prime.

It is a super-2 number, since 2×6661868024381² (a number of 26 digits) contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 6661868024381.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (6661868024341) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 3330934012190 + 3330934012191.

It is an arithmetic number, because the mean of its divisors is an integer number (3330934012191).

Almost surely, 2^{6661868024381} is an apocalyptic number.

It is an amenable number.

6661868024381 is a deficient number, since it is larger than the sum of its proper divisors (1).

6661868024381 is an equidigital number, since it uses as much as digits as its factorization.

6661868024381 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 15925248, while the sum is 59.

The spelling of 6661868024381 in words is "six trillion, six hundred sixty-one billion, eight hundred sixty-eight million, twenty-four thousand, three hundred eighty-one".