671728 has 10 divisors (see below), whose sum is σ = 1301504. Its totient is φ = 335856.

The previous prime is 671717. The next prime is 671729. The reversal of 671728 is 827176.

It is a happy number.

It is a self number, because there is not a number n which added to its sum of digits gives 671728.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (671729) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 20976 + ... + 21007.

2⁶⁷¹⁷²⁸ is an apocalyptic number.

It is an amenable number.

671728 is a deficient number, since it is larger than the sum of its proper divisors (629776).

671728 is a wasteful number, since it uses less digits than its factorization.

671728 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 41991 (or 41985 counting only the distinct ones).

The product of its digits is 4704, while the sum is 31.

The square root of 671728 is about 819.5901414732. The cubic root of 671728 is about 87.5785634529.

The spelling of 671728 in words is "six hundred seventy-one thousand, seven hundred twenty-eight".