667739 has 4 divisors (see below), whose sum is σ = 685824. Its totient is φ = 649656.

The previous prime is 667727. The next prime is 667741. The reversal of 667739 is 937766.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 937766 = 2 ⋅468883.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-667739 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (667769) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 8987 + ... + 9060.

It is an arithmetic number, because the mean of its divisors is an integer number (171456).

2⁶⁶⁷⁷³⁹ is an apocalyptic number.

667739 is a deficient number, since it is larger than the sum of its proper divisors (18085).

667739 is a wasteful number, since it uses less digits than its factorization.

667739 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 18084.

The product of its digits is 47628, while the sum is 38.

The square root of 667739 is about 817.1529844527. The cubic root of 667739 is about 87.4048598554.

The spelling of 667739 in words is "six hundred sixty-seven thousand, seven hundred thirty-nine".