6668643251 has 2 divisors, whose sum is σ = 6668643252. Its totient is φ = 6668643250.

The previous prime is 6668643239. The next prime is 6668643287. The reversal of 6668643251 is 1523468666.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 6668643251 - 2¹⁸ = 6668381107 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 6668643196 and 6668643205.

It is not a weakly prime, because it can be changed into another prime (6668643211) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 3334321625 + 3334321626.

It is an arithmetic number, because the mean of its divisors is an integer number (3334321626).

Almost surely, 2^6668643251 is an apocalyptic number.

6668643251 is a deficient number, since it is larger than the sum of its proper divisors (1).

6668643251 is an equidigital number, since it uses as much as digits as its factorization.

6668643251 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1244160, while the sum is 47.

The square root of 6668643251 is about 81661.7612533553. The cubic root of 6668643251 is about 1882.2580430897.

The spelling of 6668643251 in words is "six billion, six hundred sixty-eight million, six hundred forty-three thousand, two hundred fifty-one".