631728 has 60 divisors (see below), whose sum is σ = 1828008. Its totient is φ = 203520.

The previous prime is 631723. The next prime is 631733. The reversal of 631728 is 827136.

631728 is a `hidden beast` number, since 631 + 7 + 28 = 666.

It is an interprime number because it is at equal distance from previous prime (631723) and next prime (631733).

It is a Smith number, since the sum of its digits (27) coincides with the sum of the digits of its prime factors.

It is not an unprimeable number, because it can be changed into a prime (631723) by changing a digit.

631728 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 11 ways as a sum of consecutive naturals, for example, 5851 + ... + 5957.

2⁶³¹⁷²⁸ 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 631728, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (914004).

631728 is an abundant number, since it is smaller than the sum of its proper divisors (1196280).

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

631728 is a wasteful number, since it uses less digits than its factorization.

631728 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 162 (or 153 counting only the distinct ones).

The product of its digits is 2016, while the sum is 27.

The square root of 631728 is about 794.8131855977. The cubic root of 631728 is about 85.8044955018.

The spelling of 631728 in words is "six hundred thirty-one thousand, seven hundred twenty-eight".