664997 has 2 divisors, whose sum is σ = 664998. Its totient is φ = 664996.

The previous prime is 664973. The next prime is 665011. The reversal of 664997 is 799466.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 662596 + 2401 = 814^2 + 49^2 .

It is a cyclic number.

It is not a de Polignac number, because 664997 - 2⁶ = 664933 is a prime.

It is a plaindrome in base 14.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (664967) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 332498 + 332499.

It is an arithmetic number, because the mean of its divisors is an integer number (332499).

2⁶⁶⁴⁹⁹⁷ is an apocalyptic number.

It is an amenable number.

664997 is a deficient number, since it is larger than the sum of its proper divisors (1).

664997 is an equidigital number, since it uses as much as digits as its factorization.

664997 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 81648, while the sum is 41.

The square root of 664997 is about 815.4734820949. The cubic root of 664997 is about 87.2850560957.

It can be divided in two parts, 664 and 997, that added together give a palindrome (1661).

The spelling of 664997 in words is "six hundred sixty-four thousand, nine hundred ninety-seven".