728639 has 2 divisors, whose sum is σ = 728640. Its totient is φ = 728638.

The previous prime is 728627. The next prime is 728647. The reversal of 728639 is 936827.

728639 is nontrivially palindromic in base 15.

It is a strong prime.

It is an emirp because it is prime and its reverse (936827) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 728639 - 2⁸ = 728383 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 728599 and 728608.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (728659) by changing a digit.

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

It is a good prime.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 364319 + 364320.

It is an arithmetic number, because the mean of its divisors is an integer number (364320).

2⁷²⁸⁶³⁹ is an apocalyptic number.

728639 is a deficient number, since it is larger than the sum of its proper divisors (1).

728639 is an equidigital number, since it uses as much as digits as its factorization.

728639 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 18144, while the sum is 35.

The square root of 728639 is about 853.6035379496. The cubic root of 728639 is about 89.9851415800.

The spelling of 728639 in words is "seven hundred twenty-eight thousand, six hundred thirty-nine".