6440540 has 24 divisors (see below), whose sum is σ = 13841520. Its totient is φ = 2515968.

The previous prime is 6440537. The next prime is 6440543. The reversal of 6440540 is 450446.

It is a happy number.

6440540 is digitally balanced in base 5, because in such base it contains all the possibile digits an equal number of times.

It is an interprime number because it is at equal distance from previous prime (6440537) and next prime (6440543).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (6440543) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2885 + ... + 4604.

It is an arithmetic number, because the mean of its divisors is an integer number (576730).

Almost surely, 2^6440540 is an apocalyptic number.

It is an amenable number.

6440540 is an abundant number, since it is smaller than the sum of its proper divisors (7400980).

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

6440540 is a wasteful number, since it uses less digits than its factorization.

6440540 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7541 (or 7539 counting only the distinct ones).

The product of its (nonzero) digits is 1920, while the sum is 23.

The square root of 6440540 is about 2537.8219007645. The cubic root of 6440540 is about 186.0547493663.

Adding to 6440540 its reverse (450446), we get a palindrome (6890986).

It can be divided in two parts, 64 and 40540, that added together give a palindrome (40604).

The spelling of 6440540 in words is "six million, four hundred forty thousand, five hundred forty".