6400240 has 80 divisors (see below), whose sum is σ = 18570240. Its totient is φ = 1992960.

The previous prime is 6400231. The next prime is 6400241. The reversal of 6400240 is 420046.

It is a tau number, because it is divible by the number of its divisors (80).

It is a Harshad number since it is a multiple of its sum of digits (16).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (6400241) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 5641 + ... + 6679.

It is an arithmetic number, because the mean of its divisors is an integer number (232128).

Almost surely, 2^6400240 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 6400240, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (9285120).

6400240 is an abundant number, since it is smaller than the sum of its proper divisors (12170000).

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

6400240 is a wasteful number, since it uses less digits than its factorization.

6400240 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1070 (or 1064 counting only the distinct ones).

The product of its (nonzero) digits is 192, while the sum is 16.

The square root of 6400240 is about 2529.8695618549. The cubic root of 6400240 is about 185.6658741099.

Adding to 6400240 its reverse (420046), we get a palindrome (6820286).

The spelling of 6400240 in words is "six million, four hundred thousand, two hundred forty".