6440724 has 18 divisors (see below), whose sum is σ = 16280810. Its totient is φ = 2146896.

The previous prime is 6440723. The next prime is 6440737. The reversal of 6440724 is 4270446.

6440724 is digitally balanced in base 5, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in only one way, i.e., 5904900 + 535824 = 2430^2 + 732^2 .

It is a tau number, because it is divible by the number of its divisors (18).

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 5 ways as a sum of consecutive naturals, for example, 89419 + ... + 89490.

Almost surely, 2^6440724 is an apocalyptic number.

It is an amenable number.

6440724 is an abundant number, since it is smaller than the sum of its proper divisors (9840086).

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

6440724 is a wasteful number, since it uses less digits than its factorization.

6440724 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 178919 (or 178914 counting only the distinct ones).

The product of its (nonzero) digits is 5376, while the sum is 27.

The square root of 6440724 is about 2537.8581520645. The cubic root of 6440724 is about 186.0565211509.

The spelling of 6440724 in words is "six million, four hundred forty thousand, seven hundred twenty-four".