123816 has 64 divisors (see below), whose sum is σ = 391680. Its totient is φ = 31680.

The previous prime is 123803. The next prime is 123817. The reversal of 123816 is 618321.

It is a Harshad number since it is a multiple of its sum of digits (21).

It is a nude number because it is divisible by every one of its digits.

It is an alternating number because its digits alternate between odd and even.

It is a junction number, because it is equal to n+sod(n) for n = 123792 and 123801.

It is not an unprimeable number, because it can be changed into a prime (123817) by changing a digit.

123816 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1815 + ... + 1881.

It is an arithmetic number, because the mean of its divisors is an integer number (6120).

2¹²³⁸¹⁶ is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 123816, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (195840).

123816 is an abundant number, since it is smaller than the sum of its proper divisors (267864).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

123816 is a wasteful number, since it uses less digits than its factorization.

123816 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 94 (or 90 counting only the distinct ones).

The product of its digits is 288, while the sum is 21.

The square root of 123816 is about 351.8749777975. The cubic root of 123816 is about 49.8416322561.

It can be divided in two parts, 123 and 816, that added together give a palindrome (939).

The spelling of 123816 in words is "one hundred twenty-three thousand, eight hundred sixteen".