6638220 has 96 divisors (see below), whose sum is σ = 21772800. Its totient is φ = 1674432.

The previous prime is 6638179. The next prime is 6638221. The reversal of 6638220 is 228366.

6638220 is a `hidden beast` number, since 6 + 638 + 2 + 20 = 666.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (6638221) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 9937 + ... + 10583.

It is an arithmetic number, because the mean of its divisors is an integer number (226800).

Almost surely, 2^6638220 is an apocalyptic number.

6638220 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 6638220, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (10886400).

6638220 is an abundant number, since it is smaller than the sum of its proper divisors (15134580).

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

6638220 is a wasteful number, since it uses less digits than its factorization.

6638220 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 684 (or 676 counting only the distinct ones).

The product of its (nonzero) digits is 3456, while the sum is 27.

The square root of 6638220 is about 2576.4743352108. The cubic root of 6638220 is about 187.9391307395.

The spelling of 6638220 in words is "six million, six hundred thirty-eight thousand, two hundred twenty".