6400128 has 64 divisors (see below), whose sum is σ = 19437120. Its totient is φ = 1827840.

The previous prime is 6400123. The next prime is 6400139. The reversal of 6400128 is 8210046.

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 (21).

It is not an unprimeable number, because it can be changed into a prime (6400123) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1498 + ... + 3878.

It is an arithmetic number, because the mean of its divisors is an integer number (303705).

Almost surely, 2^6400128 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 6400128, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (9718560).

6400128 is an abundant number, since it is smaller than the sum of its proper divisors (13036992).

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

6400128 is a wasteful number, since it uses less digits than its factorization.

6400128 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2405 (or 2393 counting only the distinct ones).

The product of its (nonzero) digits is 384, while the sum is 21.

The square root of 6400128 is about 2529.8474262295. The cubic root of 6400128 is about 185.6647910933.

The spelling of 6400128 in words is "six million, four hundred thousand, one hundred twenty-eight".