6721667 has 2 divisors, whose sum is σ = 6721668. Its totient is φ = 6721666.

The previous prime is 6721661. The next prime is 6721669. The reversal of 6721667 is 7661276.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 6721667 - 2⁸ = 6721411 is a prime.

Together with 6721669, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (6721661) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 3360833 + 3360834.

It is an arithmetic number, because the mean of its divisors is an integer number (3360834).

Almost surely, 2^6721667 is an apocalyptic number.

6721667 is a deficient number, since it is larger than the sum of its proper divisors (1).

6721667 is an equidigital number, since it uses as much as digits as its factorization.

6721667 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 21168, while the sum is 35.

The square root of 6721667 is about 2592.6177890310. The cubic root of 6721667 is about 188.7233618826.

The spelling of 6721667 in words is "six million, seven hundred twenty-one thousand, six hundred sixty-seven".