6638389 has 4 divisors (see below), whose sum is σ = 6706924. Its totient is φ = 6569856.

The previous prime is 6638377. The next prime is 6638393. The reversal of 6638389 is 9838366.

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

It can be written as a sum of positive squares in 2 ways, for example, as 3452164 + 3186225 = 1858^2 + 1785^2 .

It is a cyclic number.

It is not a de Polignac number, because 6638389 - 2⁹ = 6637877 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (6638339) 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, 34122 + ... + 34315.

It is an arithmetic number, because the mean of its divisors is an integer number (1676731).

Almost surely, 2^6638389 is an apocalyptic number.

It is an amenable number.

6638389 is a deficient number, since it is larger than the sum of its proper divisors (68535).

6638389 is an equidigital number, since it uses as much as digits as its factorization.

6638389 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 68534.

The product of its digits is 186624, while the sum is 43.

The square root of 6638389 is about 2576.5071317580. The cubic root of 6638389 is about 187.9407256170.

The spelling of 6638389 in words is "six million, six hundred thirty-eight thousand, three hundred eighty-nine".