3721728 has 40 divisors (see below), whose sum is σ = 9919008. Its totient is φ = 1240064.

The previous prime is 3721727. The next prime is 3721741. The reversal of 3721728 is 8271273.

It is a junction number, because it is equal to n+sod(n) for n = 3721695 and 3721704.

It is not an unprimeable number, because it can be changed into a prime (3721721) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 325 + ... + 2747.

Almost surely, 2^3721728 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 3721728, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (4959504).

3721728 is an abundant number, since it is smaller than the sum of its proper divisors (6197280).

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

3721728 is an equidigital number, since it uses as much as digits as its factorization.

3721728 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2444 (or 2428 counting only the distinct ones).

The product of its digits is 4704, while the sum is 30.

The square root of 3721728 is about 1929.1780633213. The cubic root of 3721728 is about 154.9702058585.

The spelling of 3721728 in words is "three million, seven hundred twenty-one thousand, seven hundred twenty-eight".