6440720 has 80 divisors (see below), whose sum is σ = 17623872. Its totient is φ = 2158080.

The previous prime is 6440699. The next prime is 6440723. The reversal of 6440720 is 270446.

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

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 15 ways as a sum of consecutive naturals, for example, 11159 + ... + 11721.

Almost surely, 2^6440720 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 6440720, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (8811936).

6440720 is an abundant number, since it is smaller than the sum of its proper divisors (11183152).

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

6440720 is a wasteful number, since it uses less digits than its factorization.

6440720 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 600 (or 594 counting only the distinct ones).

The product of its (nonzero) digits is 1344, while the sum is 23.

The square root of 6440720 is about 2537.8573639982. The cubic root of 6440720 is about 186.0564826342.

The spelling of 6440720 in words is "six million, four hundred forty thousand, seven hundred twenty".