6643667 has 2 divisors, whose sum is σ = 6643668. Its totient is φ = 6643666.

The previous prime is 6643649. The next prime is 6643687. The reversal of 6643667 is 7663466.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 6643667 - 2⁸ = 6643411 is a prime.

It is a super-2 number, since 2×6643667² = 88276622413778, which contains 22 as substring.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 6643667.

It is not a weakly prime, because it can be changed into another prime (6643607) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 3321833 + 3321834.

It is an arithmetic number, because the mean of its divisors is an integer number (3321834).

Almost surely, 2^6643667 is an apocalyptic number.

6643667 is a deficient number, since it is larger than the sum of its proper divisors (1).

6643667 is an equidigital number, since it uses as much as digits as its factorization.

6643667 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 108864, while the sum is 38.

The square root of 6643667 is about 2577.5311831285. The cubic root of 6643667 is about 187.9905212514.

The spelling of 6643667 in words is "six million, six hundred forty-three thousand, six hundred sixty-seven".