123609 has 4 divisors (see below), whose sum is σ = 164816.
Its totient is φ = 82404.
The previous prime is 123601. The next prime is 123619. The reversal of 123609 is 906321.
It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.
It is not a de Polignac number, because 123609 - 23 = 123601 is a prime.
It is a D-number.
It is a Duffinian number.
It is not an unprimeable number, because it can be changed into a prime (123601) 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, 20599 + ... + 20604.
It is an arithmetic number, because the mean of its divisors is an integer number (41204).
2123609 is an apocalyptic number.
It is an amenable number.
123609 is a deficient number, since it is larger than the sum of its proper divisors (41207).
123609 is an equidigital number, since it uses as much as digits as its factorization.
123609 is an evil number, because the sum of its binary digits is even.
The sum of its prime factors is 41206.
The product of its (nonzero) digits is 324, while the sum is 21.
The square root of 123609 is about 351.5807161947.
The cubic root of 123609 is about 49.8138410907.
The spelling of 123609 in words is "one hundred twenty-three thousand, six hundred nine".