123956139 has 4 divisors (see below), whose sum is σ = 165274856. Its totient is φ = 82637424.

The previous prime is 123956137. The next prime is 123956149. The reversal of 123956139 is 931659321.

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

It is not a de Polignac number, because 123956139 - 2¹ = 123956137 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 123956097 and 123956106.

It is not an unprimeable number, because it can be changed into a prime (123956137) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 20659354 + ... + 20659359.

It is an arithmetic number, because the mean of its divisors is an integer number (41318714).

Almost surely, 2^123956139 is an apocalyptic number.

123956139 is a deficient number, since it is larger than the sum of its proper divisors (41318717).

123956139 is an equidigital number, since it uses as much as digits as its factorization.

123956139 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 41318716.

The product of its digits is 43740, while the sum is 39.

The square root of 123956139 is about 11133.5591344368. The cubic root of 123956139 is about 498.6042929622.

The spelling of 123956139 in words is "one hundred twenty-three million, nine hundred fifty-six thousand, one hundred thirty-nine".