728671 has 4 divisors (see below), whose sum is σ = 771552. Its totient is φ = 685792.

The previous prime is 728659. The next prime is 728681. The reversal of 728671 is 176827.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 176827 = 7 ⋅25261.

It is a cyclic number.

It is not a de Polignac number, because 728671 - 2⁵ = 728639 is a prime.

It is a super-2 number, since 2×728671² = 1061922852482, which contains 22 as substring.

It is a Smith number, since the sum of its digits (31) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (728681) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 21415 + ... + 21448.

It is an arithmetic number, because the mean of its divisors is an integer number (192888).

2⁷²⁸⁶⁷¹ is an apocalyptic number.

728671 is a deficient number, since it is larger than the sum of its proper divisors (42881).

728671 is a wasteful number, since it uses less digits than its factorization.

728671 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 42880.

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

The square root of 728671 is about 853.6222818085. The cubic root of 728671 is about 89.9864588681.

The spelling of 728671 in words is "seven hundred twenty-eight thousand, six hundred seventy-one".