6640178440 has 128 divisors (see below), whose sum is σ = 17408286720. Its totient is φ = 2232518400.

The previous prime is 6640178431. The next prime is 6640178443. The reversal of 6640178440 is 448710466.

It is a Harshad number since it is a multiple of its sum of digits (40).

It is a junction number, because it is equal to n+sod(n) for n = 6640178393 and 6640178402.

It is not an unprimeable number, because it can be changed into a prime (6640178443) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 4193889 + ... + 4195471.

It is an arithmetic number, because the mean of its divisors is an integer number (136002240).

Almost surely, 2^6640178440 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 6640178440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (8704143360).

6640178440 is an abundant number, since it is smaller than the sum of its proper divisors (10768108280).

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

6640178440 is a wasteful number, since it uses less digits than its factorization.

6640178440 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1883 (or 1879 counting only the distinct ones).

The product of its (nonzero) digits is 129024, while the sum is 40.

The square root of 6640178440 is about 81487.2900518848. The cubic root of 6640178440 is about 1879.5761116147.

The spelling of 6640178440 in words is "six billion, six hundred forty million, one hundred seventy-eight thousand, four hundred forty".