123865 has 8 divisors (see below), whose sum is σ = 169920. Its totient is φ = 84912.

The previous prime is 123863. The next prime is 123887. The reversal of 123865 is 568321.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 123865 - 2¹ = 123863 is a prime.

It is not an unprimeable number, because it can be changed into a prime (123863) 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 7 ways as a sum of consecutive naturals, for example, 1735 + ... + 1804.

It is an arithmetic number, because the mean of its divisors is an integer number (21240).

2¹²³⁸⁶⁵ is an apocalyptic number.

It is an amenable number.

123865 is a deficient number, since it is larger than the sum of its proper divisors (46055).

123865 is an equidigital number, since it uses as much as digits as its factorization.

123865 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3551.

The product of its digits is 1440, while the sum is 25.

The square root of 123865 is about 351.9445979128. The cubic root of 123865 is about 49.8482063065.

The spelling of 123865 in words is "one hundred twenty-three thousand, eight hundred sixty-five".