3220728 has 64 divisors (see below), whose sum is σ = 9696000. Its totient is φ = 870912.

The previous prime is 3220727. The next prime is 3220771. The reversal of 3220728 is 8270223.

It is a Harshad number since it is a multiple of its sum of digits (24).

It is a junction number, because it is equal to n+sod(n) for n = 3220698 and 3220707.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (3220727) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 2688 + ... + 3696.

It is an arithmetic number, because the mean of its divisors is an integer number (151500).

Almost surely, 2^3220728 is an apocalyptic number.

3220728 is a gapful number since it is divisible by the number (38) 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 3220728, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (4848000).

3220728 is an abundant number, since it is smaller than the sum of its proper divisors (6475272).

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

3220728 is a wasteful number, since it uses less digits than its factorization.

3220728 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1044 (or 1040 counting only the distinct ones).

The product of its (nonzero) digits is 1344, while the sum is 24.

The square root of 3220728 is about 1794.6386822979. The cubic root of 3220728 is about 147.6787529294.

The spelling of 3220728 in words is "three million, two hundred twenty thousand, seven hundred twenty-eight".