6643439 has 4 divisors (see below), whose sum is σ = 7247400. Its totient is φ = 6039480.

The previous prime is 6643423. The next prime is 6643453. The reversal of 6643439 is 9343466.

It is a happy number.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 6643439 - 2⁴ = 6643423 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 6643399 and 6643408.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (6643489) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 301964 + ... + 301985.

It is an arithmetic number, because the mean of its divisors is an integer number (1811850).

Almost surely, 2^6643439 is an apocalyptic number.

6643439 is a deficient number, since it is larger than the sum of its proper divisors (603961).

6643439 is a wasteful number, since it uses less digits than its factorization.

6643439 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 603960.

The product of its digits is 46656, while the sum is 35.

The square root of 6643439 is about 2577.4869543802. The cubic root of 6643439 is about 187.9883707157.

The spelling of 6643439 in words is "six million, six hundred forty-three thousand, four hundred thirty-nine".