679729 has 4 divisors (see below), whose sum is σ = 682084. Its totient is φ = 677376.

The previous prime is 679709. The next prime is 679733. The reversal of 679729 is 927976.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 388129 + 291600 = 623^2 + 540^2 .

It is a 3-Lehmer number, since φ(679729) divides (679729-1)³.

It is a cyclic number.

It is not a de Polignac number, because 679729 - 2¹¹ = 677681 is a prime.

It is a Duffinian number.

679729 is a lucky number.

It is a junction number, because it is equal to n+sod(n) for n = 679691 and 679700.

It is not an unprimeable number, because it can be changed into a prime (679709) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 672 + ... + 1345.

It is an arithmetic number, because the mean of its divisors is an integer number (170521).

It is a Poulet number, since it divides 2⁶⁷⁹⁷²⁸-1.

2⁶⁷⁹⁷²⁹ is an apocalyptic number.

It is an amenable number.

679729 is a deficient number, since it is larger than the sum of its proper divisors (2355).

679729 is a wasteful number, since it uses less digits than its factorization.

679729 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2354.

The product of its digits is 47628, while the sum is 40.

The square root of 679729 is about 824.4567908629. The cubic root of 679729 is about 87.9249101180.

The spelling of 679729 in words is "six hundred seventy-nine thousand, seven hundred twenty-nine".