6639687 has 24 divisors (see below), whose sum is σ = 9990656. Its totient is φ = 4245696.

The previous prime is 6639679. The next prime is 6639697. The reversal of 6639687 is 7869366.

6639687 is a `hidden beast` number, since 6 + 639 + 6 + 8 + 7 = 666.

It is not a de Polignac number, because 6639687 - 2³ = 6639679 is a prime.

It is a Duffinian number.

Its product of digits (326592) is a multiple of the sum of its prime divisors (324).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (6639697) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 42213 + ... + 42369.

Almost surely, 2^6639687 is an apocalyptic number.

6639687 is a deficient number, since it is larger than the sum of its proper divisors (3350969).

6639687 is a wasteful number, since it uses less digits than its factorization.

6639687 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 327 (or 324 counting only the distinct ones).

The product of its digits is 326592, while the sum is 45.

The square root of 6639687 is about 2576.7590108506. The cubic root of 6639687 is about 187.9529741291.

The spelling of 6639687 in words is "six million, six hundred thirty-nine thousand, six hundred eighty-seven".