664667 has 2 divisors, whose sum is σ = 664668. Its totient is φ = 664666.

The previous prime is 664663. The next prime is 664669. The reversal of 664667 is 766466.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 664667 - 2² = 664663 is a prime.

Together with 664669, it forms a pair of twin primes.

It is a Chen prime.

It is a plaindrome in base 9.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 664667.

It is not a weakly prime, because it can be changed into another prime (664661) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 332333 + 332334.

It is an arithmetic number, because the mean of its divisors is an integer number (332334).

2⁶⁶⁴⁶⁶⁷ is an apocalyptic number.

664667 is a deficient number, since it is larger than the sum of its proper divisors (1).

664667 is an equidigital number, since it uses as much as digits as its factorization.

664667 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 36288, while the sum is 35.

The square root of 664667 is about 815.2711205483. The cubic root of 664667 is about 87.2706155121.

It can be divided in two parts, 664 and 667, that added together give a palindrome (1331).

The spelling of 664667 in words is "six hundred sixty-four thousand, six hundred sixty-seven".