393121728 has 56 divisors (see below), whose sum is σ = 1155710160. Its totient is φ = 131040000.

The previous prime is 393121721. The next prime is 393121741. The reversal of 393121728 is 827121393.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a junction number, because it is equal to n+sod(n) for n = 393121692 and 393121701.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (393121721) 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, 112023 + ... + 115478.

Almost surely, 2^393121728 is an apocalyptic number.

It is an amenable number.

393121728 is an abundant number, since it is smaller than the sum of its proper divisors (762588432).

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

393121728 is a wasteful number, since it uses less digits than its factorization.

393121728 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 227522 (or 227506 counting only the distinct ones).

The product of its digits is 18144, while the sum is 36.

The square root of 393121728 is about 19827.2975465644. The cubic root of 393121728 is about 732.5585631908.

The spelling of 393121728 in words is "three hundred ninety-three million, one hundred twenty-one thousand, seven hundred twenty-eight".