6866639 has 12 divisors (see below), whose sum is σ = 7624512. Its totient is φ = 6177600.

The previous prime is 6866633. The next prime is 6866647. The reversal of 6866639 is 9366686.

6866639 = T₃₈₀ + T₃₈₁ + ... + T₄₅₇.

It is not a de Polignac number, because 6866639 - 2⁸ = 6866383 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 6866639.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (6866633) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 6434 + ... + 7424.

It is an arithmetic number, because the mean of its divisors is an integer number (635376).

Almost surely, 2^6866639 is an apocalyptic number.

6866639 is a deficient number, since it is larger than the sum of its proper divisors (757873).

6866639 is a wasteful number, since it uses less digits than its factorization.

6866639 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1058 (or 1045 counting only the distinct ones).

The product of its digits is 279936, while the sum is 44.

The square root of 6866639 is about 2620.4272552391. The cubic root of 6866639 is about 190.0705093800.

The spelling of 6866639 in words is "six million, eight hundred sixty-six thousand, six hundred thirty-nine".