6440000 has 140 divisors (see below), whose sum is σ = 19043904. Its totient is φ = 2112000.

The previous prime is 6439997. The next prime is 6440003. The reversal of 6440000 is 446.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (6439997) and next prime (6440003).

It is a tau number, because it is divible by the number of its divisors (140).

It is a Harshad number since it is a multiple of its sum of digits (14).

It is a nialpdrome in base 10.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (6440003) by changing a digit.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 279989 + ... + 280011.

Almost surely, 2^6440000 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 6440000, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (9521952).

6440000 is an abundant number, since it is smaller than the sum of its proper divisors (12603904).

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

6440000 is an equidigital number, since it uses as much as digits as its factorization.

6440000 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 62 (or 37 counting only the distinct ones).

The product of its (nonzero) digits is 96, while the sum is 14.

The square root of 6440000 is about 2537.7155080899. The cubic root of 6440000 is about 186.0495493690.

Adding to 6440000 its reverse (446), we get a palindrome (6440446).

It can be divided in two parts, 64 and 40000, that multiplied together give a 4-th power (2560000 = 40⁴).

The spelling of 6440000 in words is "six million, four hundred forty thousand".