6668640 has 144 divisors (see below), whose sum is σ = 24884496. Its totient is φ = 1612800.

The previous prime is 6668617. The next prime is 6668659. The reversal of 6668640 is 468666.

6668640 = T₂₀₅ + T₂₀₆ + ... + T₃₆₄.

It is a tau number, because it is divible by the number of its divisors (144).

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a junction number, because it is equal to n+sod(n) for n = 6668595 and 6668604.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 15630 + ... + 16050.

It is an arithmetic number, because the mean of its divisors is an integer number (172809).

Almost surely, 2^6668640 is an apocalyptic number.

6668640 is a gapful number since it is divisible by the number (60) 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 6668640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (12442248).

6668640 is an abundant number, since it is smaller than the sum of its proper divisors (18215856).

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

6668640 is a wasteful number, since it uses less digits than its factorization.

6668640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 453 (or 442 counting only the distinct ones).

The product of its (nonzero) digits is 41472, while the sum is 36.

The square root of 6668640 is about 2582.3710035547. The cubic root of 6668640 is about 188.2257737219.

The spelling of 6668640 in words is "six million, six hundred sixty-eight thousand, six hundred forty".