667909 has 4 divisors (see below), whose sum is σ = 728640. Its totient is φ = 607180.

The previous prime is 667903. The next prime is 667921. The reversal of 667909 is 909766.

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 a cyclic number.

It is not a de Polignac number, because 667909 - 2⁷ = 667781 is a prime.

It is a super-2 number, since 2×667909² = 892204864562, which contains 22 as substring.

667909 is a lucky number.

It is a plaindrome in base 14.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (667903) 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, 30349 + ... + 30370.

It is an arithmetic number, because the mean of its divisors is an integer number (182160).

2⁶⁶⁷⁹⁰⁹ is an apocalyptic number.

It is an amenable number.

667909 is a deficient number, since it is larger than the sum of its proper divisors (60731).

667909 is a wasteful number, since it uses less digits than its factorization.

667909 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 60730.

The product of its (nonzero) digits is 20412, while the sum is 37.

The square root of 667909 is about 817.2569975228. The cubic root of 667909 is about 87.4122767081.

The spelling of 667909 in words is "six hundred sixty-seven thousand, nine hundred nine".