6639894 has 40 divisors (see below), whose sum is σ = 15760008. Its totient is φ = 2082240.

The previous prime is 6639889. The next prime is 6639907. The reversal of 6639894 is 4989366.

6639894 is a `hidden beast` number, since 6 + 639 + 8 + 9 + 4 = 666.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 1549 + ... + 3959.

Almost surely, 2^6639894 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 6639894, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (7880004).

6639894 is an abundant number, since it is smaller than the sum of its proper divisors (9120114).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

6639894 is a wasteful number, since it uses less digits than its factorization.

6639894 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2442 (or 2433 counting only the distinct ones).

The product of its digits is 279936, while the sum is 45.

The square root of 6639894 is about 2576.7991772740. The cubic root of 6639894 is about 187.9549273267.

The spelling of 6639894 in words is "six million, six hundred thirty-nine thousand, eight hundred ninety-four".