665213 has 2 divisors, whose sum is σ = 665214.
Its totient is φ = 665212.
The previous prime is 665207. The next prime is 665221. The reversal of 665213 is 312566.
It is a weak prime.
It can be written as a sum of positive squares in only one way, i.e., 375769 + 289444 = 613^2 + 538^2
It is a cyclic number.
It is not a de Polignac number, because 665213 - 212 = 661117 is a prime.
It is a plaindrome in base 9.
It is a congruent number.
It is not a weakly prime, because it can be changed into another prime (665233) by changing a digit.
It is a pernicious number, because its binary representation contains a prime number (11) of ones.
It is a polite number, since it can be written as a sum of consecutive naturals, namely, 332606 + 332607.
It is an arithmetic number, because the mean of its divisors is an integer number (332607).
2665213 is an apocalyptic number.
It is an amenable number.
665213 is a deficient number, since it is larger than the sum of its proper divisors (1).
665213 is an equidigital number, since it uses as much as digits as its factorization.
665213 is an odious number, because the sum of its binary digits is odd.
The product of its digits is 1080, while the sum is 23.
The square root of 665213 is about 815.6059097383.
The cubic root of 665213 is about 87.2945055274.
Adding to 665213 its reverse (312566), we get a palindrome (977779).
It can be divided in two parts, 665 and 213, that added together give a palindrome (878).
The spelling of 665213 in words is "six hundred sixty-five thousand, two hundred thirteen".