6639223 has 2 divisors, whose sum is σ = 6639224. Its totient is φ = 6639222.

The previous prime is 6639209. The next prime is 6639233. The reversal of 6639223 is 3229366.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-6639223 is a prime.

6639223 is a lucky number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (6639233) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 3319611 + 3319612.

It is an arithmetic number, because the mean of its divisors is an integer number (3319612).

Almost surely, 2^6639223 is an apocalyptic number.

6639223 is a deficient number, since it is larger than the sum of its proper divisors (1).

6639223 is an equidigital number, since it uses as much as digits as its factorization.

6639223 is an evil number, because the sum of its binary digits is even.

The product of its digits is 11664, while the sum is 31.

The square root of 6639223 is about 2576.6689736945. The cubic root of 6639223 is about 187.9485957996.

The spelling of 6639223 in words is "six million, six hundred thirty-nine thousand, two hundred twenty-three".