6638720 has 128 divisors (see below), whose sum is σ = 18506880. Its totient is φ = 2252800.

The previous prime is 6638701. The next prime is 6638741. The reversal of 6638720 is 278366.

It is a tau number, because it is divible by the number of its divisors (128).

It is a Harshad number since it is a multiple of its sum of digits (32).

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 161900 + ... + 161940.

It is an arithmetic number, because the mean of its divisors is an integer number (144585).

Almost surely, 2^6638720 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 6638720, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (9253440).

6638720 is an abundant number, since it is smaller than the sum of its proper divisors (11868160).

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

6638720 is a wasteful number, since it uses less digits than its factorization.

6638720 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 94 (or 82 counting only the distinct ones).

The product of its (nonzero) digits is 12096, while the sum is 32.

The square root of 6638720 is about 2576.5713652061. The cubic root of 6638720 is about 187.9438492336.

The spelling of 6638720 in words is "six million, six hundred thirty-eight thousand, seven hundred twenty".