6440856 has 32 divisors (see below), whose sum is σ = 16208640. Its totient is φ = 2132768.

The previous prime is 6440831. The next prime is 6440873. The reversal of 6440856 is 6580446.

It is a happy number.

It is a hoax number, since the sum of its digits (33) coincides with the sum of the digits of its distinct prime factors.

It is an Ulam number.

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, 3205 + ... + 4811.

It is an arithmetic number, because the mean of its divisors is an integer number (506520).

Almost surely, 2^6440856 is an apocalyptic number.

It is an amenable number.

6440856 is an abundant number, since it is smaller than the sum of its proper divisors (9767784).

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

6440856 is a wasteful number, since it uses less digits than its factorization.

6440856 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1783 (or 1779 counting only the distinct ones).

The product of its (nonzero) digits is 23040, while the sum is 33.

The square root of 6440856 is about 2537.8841581128. The cubic root of 6440856 is about 186.0577921929.

The spelling of 6440856 in words is "six million, four hundred forty thousand, eight hundred fifty-six".