6440728 has 16 divisors (see below), whose sum is σ = 13801680. Its totient is φ = 2760288.

The previous prime is 6440723. The next prime is 6440737. The reversal of 6440728 is 8270446.

It is a self number, because there is not a number n which added to its sum of digits gives 6440728.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (6440723) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 57451 + ... + 57562.

It is an arithmetic number, because the mean of its divisors is an integer number (862605).

Almost surely, 2^6440728 is an apocalyptic number.

It is an amenable number.

6440728 is an abundant number, since it is smaller than the sum of its proper divisors (7360952).

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

6440728 is a wasteful number, since it uses less digits than its factorization.

6440728 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 115026 (or 115022 counting only the distinct ones).

The product of its (nonzero) digits is 10752, while the sum is 31.

The square root of 6440728 is about 2537.8589401304. The cubic root of 6440728 is about 186.0565596676.

The spelling of 6440728 in words is "six million, four hundred forty thousand, seven hundred twenty-eight".