6643213 has 2 divisors, whose sum is σ = 6643214. Its totient is φ = 6643212.

The previous prime is 6643211. The next prime is 6643229. The reversal of 6643213 is 3123466.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 4338889 + 2304324 = 2083^2 + 1518^2 .

It is a cyclic number.

It is not a de Polignac number, because 6643213 - 2¹ = 6643211 is a prime.

Together with 6643211, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (6643211) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 3321606 + 3321607.

It is an arithmetic number, because the mean of its divisors is an integer number (3321607).

Almost surely, 2^6643213 is an apocalyptic number.

It is an amenable number.

6643213 is a deficient number, since it is larger than the sum of its proper divisors (1).

6643213 is an equidigital number, since it uses as much as digits as its factorization.

6643213 is an evil number, because the sum of its binary digits is even.

The product of its digits is 2592, while the sum is 25.

The square root of 6643213 is about 2577.4431128543. The cubic root of 6643213 is about 187.9862389958.

Adding to 6643213 its reverse (3123466), we get a palindrome (9766679).

The spelling of 6643213 in words is "six million, six hundred forty-three thousand, two hundred thirteen".