669729 has 4 divisors (see below), whose sum is σ = 892976. Its totient is φ = 446484.

The previous prime is 669707. The next prime is 669733. The reversal of 669729 is 927966.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is not a de Polignac number, because 669729 - 2¹² = 665633 is a prime.

It is a D-number.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (669029) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 111619 + ... + 111624.

It is an arithmetic number, because the mean of its divisors is an integer number (223244).

2⁶⁶⁹⁷²⁹ is an apocalyptic number.

It is an amenable number.

669729 is a deficient number, since it is larger than the sum of its proper divisors (223247).

669729 is a wasteful number, since it uses less digits than its factorization.

669729 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 223246.

The product of its digits is 40824, while the sum is 39.

The square root of 669729 is about 818.3697208475. The cubic root of 669729 is about 87.4916019151.

The spelling of 669729 in words is "six hundred sixty-nine thousand, seven hundred twenty-nine".