212021312123 has 4 divisors (see below), whose sum is σ = 214079771568. Its totient is φ = 209962852680.

The previous prime is 212021312051. The next prime is 212021312171. The reversal of 212021312123 is 321213120212.

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-212021312123 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 212021312095 and 212021312104.

It is not an unprimeable number, because it can be changed into a prime (212021314123) 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, 1029229568 + ... + 1029229773.

It is an arithmetic number, because the mean of its divisors is an integer number (53519942892).

Almost surely, 2^212021312123 is an apocalyptic number.

212021312123 is a deficient number, since it is larger than the sum of its proper divisors (2058459445).

212021312123 is a wasteful number, since it uses less digits than its factorization.

212021312123 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2058459444.

The product of its (nonzero) digits is 288, while the sum is 20.

Adding to 212021312123 its reverse (321213120212), we get a palindrome (533234432335).

The spelling of 212021312123 in words is "two hundred twelve billion, twenty-one million, three hundred twelve thousand, one hundred twenty-three".