6439640 has 32 divisors (see below), whose sum is σ = 14580000. Its totient is φ = 2559744.

The previous prime is 6439639. The next prime is 6439679. The reversal of 6439640 is 469346.

It is a junction number, because it is equal to n+sod(n) for n = 6439597 and 6439606.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 7556 + ... + 8364.

It is an arithmetic number, because the mean of its divisors is an integer number (455625).

Almost surely, 2^6439640 is an apocalyptic number.

It is an amenable number.

6439640 is an abundant number, since it is smaller than the sum of its proper divisors (8140360).

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

6439640 is a wasteful number, since it uses less digits than its factorization.

6439640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1019 (or 1015 counting only the distinct ones).

The product of its (nonzero) digits is 15552, while the sum is 32.

The square root of 6439640 is about 2537.6445771621. The cubic root of 6439640 is about 186.0460825426.

The spelling of 6439640 in words is "six million, four hundred thirty-nine thousand, six hundred forty".