123865681 has 4 divisors (see below), whose sum is σ = 124261732. Its totient is φ = 123469632.

The previous prime is 123865657. The next prime is 123865711. The reversal of 123865681 is 186568321.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 186568321 = 53 ⋅3520157.

It can be written as a sum of positive squares in 2 ways, for example, as 18105025 + 105760656 = 4255^2 + 10284^2 .

It is a cyclic number.

It is not a de Polignac number, because 123865681 - 2¹¹ = 123863633 is a prime.

It is a super-2 number, since 2×123865681² = 30685413859187522, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (123865481) 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 3 ways as a sum of consecutive naturals, for example, 197556 + ... + 198181.

It is an arithmetic number, because the mean of its divisors is an integer number (31065433).

Almost surely, 2^123865681 is an apocalyptic number.

It is an amenable number.

123865681 is a deficient number, since it is larger than the sum of its proper divisors (396051).

123865681 is an equidigital number, since it uses as much as digits as its factorization.

123865681 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 396050.

The product of its digits is 69120, while the sum is 40.

The square root of 123865681 is about 11129.4959903852. The cubic root of 123865681 is about 498.4829766016.

The spelling of 123865681 in words is "one hundred twenty-three million, eight hundred sixty-five thousand, six hundred eighty-one".