6639669 has 12 divisors (see below), whose sum is σ = 9625356. Its totient is φ = 4410432.

The previous prime is 6639653. The next prime is 6639679. The reversal of 6639669 is 9669366.

6639669 is a `hidden beast` number, since 6 + 639 + 6 + 6 + 9 = 666.

6639669 is digitally balanced in base 3, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in 2 ways, for example, as 439569 + 6200100 = 663^2 + 2490^2 .

It is not a de Polignac number, because 6639669 - 2⁴ = 6639653 is a prime.

It is a super-2 number, since 2×6639669² = 88170408859122, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (6639629) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 1639 + ... + 3995.

It is an arithmetic number, because the mean of its divisors is an integer number (802113).

Almost surely, 2^6639669 is an apocalyptic number.

It is an amenable number.

6639669 is a deficient number, since it is larger than the sum of its proper divisors (2985687).

6639669 is a wasteful number, since it uses less digits than its factorization.

6639669 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2676 (or 2673 counting only the distinct ones).

The product of its digits is 314928, while the sum is 45.

The square root of 6639669 is about 2576.7555180886. The cubic root of 6639669 is about 187.9528042839.

The spelling of 6639669 in words is "six million, six hundred thirty-nine thousand, six hundred sixty-nine".