6440820 has 24 divisors (see below), whose sum is σ = 18034464. Its totient is φ = 1717536.

The previous prime is 6440809. The next prime is 6440821. The reversal of 6440820 is 280446.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (6440821) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 53614 + ... + 53733.

It is an arithmetic number, because the mean of its divisors is an integer number (751436).

Almost surely, 2^6440820 is an apocalyptic number.

6440820 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

6440820 is an abundant number, since it is smaller than the sum of its proper divisors (11593644).

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

6440820 is a wasteful number, since it uses less digits than its factorization.

6440820 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 107359 (or 107357 counting only the distinct ones).

The product of its (nonzero) digits is 1536, while the sum is 24.

The square root of 6440820 is about 2537.8770655806. The cubic root of 6440820 is about 186.0574455468.

It can be divided in two parts, 6440 and 820, that added together give a triangular number (7260 = T₁₂₀).

The spelling of 6440820 in words is "six million, four hundred forty thousand, eight hundred twenty".