393728 has 20 divisors (see below), whose sum is σ = 787710. Its totient is φ = 196608.

The previous prime is 393727. The next prime is 393739. The reversal of 393728 is 827393.

It can be written as a sum of positive squares in only one way, i.e., 350464 + 43264 = 592^2 + 208^2 .

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

It is a junction number, because it is equal to n+sod(n) for n = 393694 and 393703.

It is not an unprimeable number, because it can be changed into a prime (393721) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (3) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 128 + ... + 896.

2³⁹³⁷²⁸ 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 393728, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (393855).

393728 is a primitive abundant number, since it is smaller than the sum of its proper divisors, none of which is abundant.

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

393728 is an frugal number, since it uses more digits than its factorization.

393728 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 787 (or 771 counting only the distinct ones).

The product of its digits is 9072, while the sum is 32.

The square root of 393728 is about 627.4774896361. The cubic root of 393728 is about 73.2934953502.

The spelling of 393728 in words is "three hundred ninety-three thousand, seven hundred twenty-eight".