397728 has 36 divisors (see below), whose sum is σ = 1131858. Its totient is φ = 132480.

The previous prime is 397723. The next prime is 397729. The reversal of 397728 is 827793.

It can be written as a sum of positive squares in only one way, i.e., 345744 + 51984 = 588^2 + 228^2 .

It is a tau number, because it is divible by the number of its divisors (36).

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

It is a nialpdrome in base 9.

It is a junction number, because it is equal to n+sod(n) for n = 397692 and 397701.

It is not an unprimeable number, because it can be changed into a prime (397721) by changing a digit.

397728 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 403 + ... + 978.

2³⁹⁷⁷²⁸ is an apocalyptic number.

It is an amenable number.

397728 is an abundant number, since it is smaller than the sum of its proper divisors (734130).

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

397728 is a wasteful number, since it uses less digits than its factorization.

397728 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1397 (or 1386 counting only the distinct ones).

The product of its digits is 21168, while the sum is 36.

The square root of 397728 is about 630.6568004866. The cubic root of 397728 is about 73.5408630197.

It can be divided in two parts, 3977 and 28, that added together give a triangular number (4005 = T₈₉).

The spelling of 397728 in words is "three hundred ninety-seven thousand, seven hundred twenty-eight".