6390440 has 64 divisors (see below), whose sum is σ = 17020800. Its totient is φ = 2112768.

The previous prime is 6390431. The next prime is 6390443. The reversal of 6390440 is 440936.

It is not an unprimeable number, because it can be changed into a prime (6390443) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 7727 + ... + 8513.

It is an arithmetic number, because the mean of its divisors is an integer number (265950).

Almost surely, 2^6390440 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 6390440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (8510400).

6390440 is an abundant number, since it is smaller than the sum of its proper divisors (10630360).

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

6390440 is a wasteful number, since it uses less digits than its factorization.

6390440 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 834 (or 830 counting only the distinct ones).

The product of its (nonzero) digits is 2592, while the sum is 26.

The square root of 6390440 is about 2527.9319611097. The cubic root of 6390440 is about 185.5710622988.

The spelling of 6390440 in words is "six million, three hundred ninety thousand, four hundred forty".