6440656 has 10 divisors (see below), whose sum is σ = 12478802. Its totient is φ = 3220320.

The previous prime is 6440647. The next prime is 6440683. The reversal of 6440656 is 6560446.

It can be written as a sum of positive squares in only one way, i.e., 6170256 + 270400 = 2484^2 + 520^2 .

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 201255 + ... + 201286.

Almost surely, 2^6440656 is an apocalyptic number.

It is an amenable number.

6440656 is a deficient number, since it is larger than the sum of its proper divisors (6038146).

6440656 is a wasteful number, since it uses less digits than its factorization.

6440656 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 402549 (or 402543 counting only the distinct ones).

The product of its (nonzero) digits is 17280, while the sum is 31.

The square root of 6440656 is about 2537.8447549052. The cubic root of 6440656 is about 186.0558663649.

The spelling of 6440656 in words is "six million, four hundred forty thousand, six hundred fifty-six".