6440144 has 20 divisors (see below), whose sum is σ = 13212324. Its totient is φ = 3030528.

The previous prime is 6440143. The next prime is 6440149. The reversal of 6440144 is 4410446.

6440144 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 2 ways, for example, as 3841600 + 2598544 = 1960^2 + 1612^2 .

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (6440141) 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, 11567 + ... + 12110.

Almost surely, 2^6440144 is an apocalyptic number.

It is an amenable number.

6440144 is an abundant number, since it is smaller than the sum of its proper divisors (6772180).

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

6440144 is a wasteful number, since it uses less digits than its factorization.

6440144 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 23702 (or 23696 counting only the distinct ones).

The product of its (nonzero) digits is 1536, while the sum is 23.

The square root of 6440144 is about 2537.7438799059. The cubic root of 6440144 is about 186.0509360634.

The spelling of 6440144 in words is "six million, four hundred forty thousand, one hundred forty-four".