123681 has 4 divisors (see below), whose sum is σ = 164912. Its totient is φ = 82452.

The previous prime is 123677. The next prime is 123701. The reversal of 123681 is 186321.

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 123681 - 2² = 123677 is a prime.

It is a super-2 number, since 2×123681² = 30593979522, which contains 22 as substring.

It is a D-number.

It is a Duffinian number.

It is a Curzon number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 123681.

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, 20611 + ... + 20616.

It is an arithmetic number, because the mean of its divisors is an integer number (41228).

2¹²³⁶⁸¹ is an apocalyptic number.

It is an amenable number.

123681 is a deficient number, since it is larger than the sum of its proper divisors (41231).

123681 is an equidigital number, since it uses as much as digits as its factorization.

123681 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 41230.

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

The square root of 123681 is about 351.6830959827. The cubic root of 123681 is about 49.8235110997.

The spelling of 123681 in words is "one hundred twenty-three thousand, six hundred eighty-one".