123138685679 has 4 divisors (see below), whose sum is σ = 123272678640. Its totient is φ = 123004692720.

The previous prime is 123138685673. The next prime is 123138685693. The reversal of 123138685679 is 976586831321.

It is a happy number.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-123138685679 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (123138685673) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 66995102 + ... + 66996939.

It is an arithmetic number, because the mean of its divisors is an integer number (30818169660).

Almost surely, 2^123138685679 is an apocalyptic number.

123138685679 is a deficient number, since it is larger than the sum of its proper divisors (133992961).

123138685679 is an equidigital number, since it uses as much as digits as its factorization.

123138685679 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 133992960.

The product of its digits is 13063680, while the sum is 59.

The spelling of 123138685679 in words is "one hundred twenty-three billion, one hundred thirty-eight million, six hundred eighty-five thousand, six hundred seventy-nine".