3999728 has 40 divisors (see below), whose sum is σ = 8332800. Its totient is φ = 1854144.

The previous prime is 3999727. The next prime is 3999733. The reversal of 3999728 is 8279993.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (3999727) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 17825 + ... + 18047.

It is an arithmetic number, because the mean of its divisors is an integer number (208320).

Almost surely, 2^3999728 is an apocalyptic number.

3999728 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 3999728, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (4166400).

3999728 is an abundant number, since it is smaller than the sum of its proper divisors (4333072).

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

3999728 is a wasteful number, since it uses less digits than its factorization.

3999728 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 309 (or 303 counting only the distinct ones).

The product of its digits is 244944, while the sum is 47.

The square root of 3999728 is about 1999.9319988440. The cubic root of 3999728 is about 158.7365070062.

The spelling of 3999728 in words is "three million, nine hundred ninety-nine thousand, seven hundred twenty-eight".