665523 has 12 divisors (see below), whose sum is σ = 992280. Its totient is φ = 440856.

The previous prime is 665507. The next prime is 665527. The reversal of 665523 is 325566.

It is a powerful number, because all its prime factors have an exponent greater than 1 and also an Achilles number because it is not a perfect power.

665523 is a `hidden beast` number, since 6 + 655 + 2 + 3 = 666.

It is not a de Polignac number, because 665523 - 2⁴ = 665507 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (27).

665523 is a lucky number.

It is not an unprimeable number, because it can be changed into a prime (665527) 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 in 11 ways as a sum of consecutive naturals, for example, 4161 + ... + 4317.

It is an arithmetic number, because the mean of its divisors is an integer number (82690).

2⁶⁶⁵⁵²³ is an apocalyptic number.

665523 is a deficient number, since it is larger than the sum of its proper divisors (326757).

665523 is an equidigital number, since it uses as much as digits as its factorization.

665523 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 323 (or 160 counting only the distinct ones).

The product of its digits is 5400, while the sum is 27.

The square root of 665523 is about 815.7959303649. The cubic root of 665523 is about 87.3080636380.

Multiplying 665523 by its sum of digits (27), we get a square (17969121 = 4239²).

665523 divided by its sum of digits (27) gives a square (24649 = 157²).

The spelling of 665523 in words is "six hundred sixty-five thousand, five hundred twenty-three".