6440064 has 64 divisors (see below), whose sum is σ = 17690880. Its totient is φ = 2073600.

The previous prime is 6440041. The next prime is 6440089. The reversal of 6440064 is 4600446.

It is a tau number, because it is divible by the number of its divisors (64).

It is a Harshad number since it is a multiple of its sum of digits (24).

It is an Ulam number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 11634 + ... + 12174.

It is an arithmetic number, because the mean of its divisors is an integer number (276420).

Almost surely, 2^6440064 is an apocalyptic number.

6440064 is a gapful number since it is divisible by the number (64) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 6440064, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (8845440).

6440064 is an abundant number, since it is smaller than the sum of its proper divisors (11250816).

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

6440064 is a wasteful number, since it uses less digits than its factorization.

6440064 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 589 (or 577 counting only the distinct ones).

The product of its (nonzero) digits is 2304, while the sum is 24.

The square root of 6440064 is about 2537.7281178251. The cubic root of 6440064 is about 186.0501656802.

The spelling of 6440064 in words is "six million, four hundred forty thousand, sixty-four".