123312120021 has 6 divisors (see below), whose sum is σ = 178117506710. Its totient is φ = 82208080008.

The previous prime is 123312119981. The next prime is 123312120031. The reversal of 123312120021 is 120021213321.

It can be written as a sum of positive squares in only one way, i.e., 68011424100 + 55300695921 = 260790^2 + 235161^2 .

It is not a de Polignac number, because 123312120021 - 2¹⁰ = 123312118997 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 123312119976 and 123312120003.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (123312120031) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 6850673326 + ... + 6850673343.

Almost surely, 2^123312120021 is an apocalyptic number.

It is an amenable number.

123312120021 is a deficient number, since it is larger than the sum of its proper divisors (54805386689).

123312120021 is a wasteful number, since it uses less digits than its factorization.

123312120021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 13701346675 (or 13701346672 counting only the distinct ones).

The product of its (nonzero) digits is 144, while the sum is 18.

Adding to 123312120021 its reverse (120021213321), we get a palindrome (243333333342).

The spelling of 123312120021 in words is "one hundred twenty-three billion, three hundred twelve million, one hundred twenty thousand, twenty-one".