664789 has 2 divisors, whose sum is σ = 664790. Its totient is φ = 664788.

The previous prime is 664777. The next prime is 664793. The reversal of 664789 is 987466.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 339889 + 324900 = 583^2 + 570^2 .

It is a cyclic number.

It is not a de Polignac number, because 664789 - 2⁵ = 664757 is a prime.

It is an Ulam number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (664739) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 332394 + 332395.

It is an arithmetic number, because the mean of its divisors is an integer number (332395).

2⁶⁶⁴⁷⁸⁹ is an apocalyptic number.

It is an amenable number.

664789 is a deficient number, since it is larger than the sum of its proper divisors (1).

664789 is an equidigital number, since it uses as much as digits as its factorization.

664789 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 72576, while the sum is 40.

The square root of 664789 is about 815.3459388505. The cubic root of 664789 is about 87.2759547089.

The spelling of 664789 in words is "six hundred sixty-four thousand, seven hundred eighty-nine".