665623 has 4 divisors (see below), whose sum is σ = 760720. Its totient is φ = 570528.

The previous prime is 665617. The next prime is 665629. The reversal of 665623 is 326566.

It is a semiprime because it is the product of two primes.

It is an interprime number because it is at equal distance from previous prime (665617) and next prime (665629).

It is not a de Polignac number, because 665623 - 2⁵ = 665591 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 665591 and 665600.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (665629) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 47538 + ... + 47551.

It is an arithmetic number, because the mean of its divisors is an integer number (190180).

2⁶⁶⁵⁶²³ is an apocalyptic number.

665623 is a deficient number, since it is larger than the sum of its proper divisors (95097).

665623 is an equidigital number, since it uses as much as digits as its factorization.

665623 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 95096.

The product of its digits is 6480, while the sum is 28.

The square root of 665623 is about 815.8572179003. The cubic root of 665623 is about 87.3124363239.

The spelling of 665623 in words is "six hundred sixty-five thousand, six hundred twenty-three".