665123 has 2 divisors, whose sum is σ = 665124. Its totient is φ = 665122.

The previous prime is 665117. The next prime is 665131. The reversal of 665123 is 321566.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 665123 - 2¹⁰ = 664099 is a prime.

It is a plaindrome in base 9 and base 14.

It is not a weakly prime, because it can be changed into another prime (665113) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 332561 + 332562.

It is an arithmetic number, because the mean of its divisors is an integer number (332562).

2⁶⁶⁵¹²³ is an apocalyptic number.

665123 is a deficient number, since it is larger than the sum of its proper divisors (1).

665123 is an equidigital number, since it uses as much as digits as its factorization.

665123 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1080, while the sum is 23.

The square root of 665123 is about 815.5507341668. The cubic root of 665123 is about 87.2905685129.

Adding to 665123 its reverse (321566), we get a palindrome (986689).

The spelling of 665123 in words is "six hundred sixty-five thousand, one hundred twenty-three".