123688681 has 4 divisors (see below), whose sum is σ = 123749332. Its totient is φ = 123628032.

The previous prime is 123688679. The next prime is 123688699. The reversal of 123688681 is 186886321.

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

It can be written as a sum of positive squares in 2 ways, for example, as 13249600 + 110439081 = 3640^2 + 10509^2 .

It is a cyclic number.

It is not a de Polignac number, because 123688681 - 2¹ = 123688679 is a prime.

It is a super-2 number, since 2×123688681² = 30597779615039522, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (123680681) 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, 27156 + ... + 31381.

It is an arithmetic number, because the mean of its divisors is an integer number (30937333).

Almost surely, 2^123688681 is an apocalyptic number.

It is an amenable number.

123688681 is a deficient number, since it is larger than the sum of its proper divisors (60651).

123688681 is an equidigital number, since it uses as much as digits as its factorization.

123688681 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 60650.

The product of its digits is 110592, while the sum is 43.

The square root of 123688681 is about 11121.5413050530. The cubic root of 123688681 is about 498.2454248004.

The spelling of 123688681 in words is "one hundred twenty-three million, six hundred eighty-eight thousand, six hundred eighty-one".