212123122242421 has 4 divisors (see below), whose sum is σ = 228440285491852. Its totient is φ = 195805958992992.

The previous prime is 212123122242413. The next prime is 212123122242443. The reversal of 212123122242421 is 124242221321212.

212123122242421 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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

It can be written as a sum of positive squares in 2 ways, for example, as 24033143374321 + 188089978868100 = 4902361^2 + 13714590^2 .

It is a cyclic number.

It is not a de Polignac number, because 212123122242421 - 2³ = 212123122242413 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 (212123122242401) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 8158581624696 + ... + 8158581624721.

It is an arithmetic number, because the mean of its divisors is an integer number (57110071372963).

Almost surely, 2^{212123122242421} is an apocalyptic number.

It is an amenable number.

212123122242421 is a deficient number, since it is larger than the sum of its proper divisors (16317163249431).

212123122242421 is a wasteful number, since it uses less digits than its factorization.

212123122242421 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 16317163249430.

The product of its digits is 12288, while the sum is 31.

Adding to 212123122242421 its reverse (124242221321212), we get a palindrome (336365343563633).

The spelling of 212123122242421 in words is "two hundred twelve trillion, one hundred twenty-three billion, one hundred twenty-two million, two hundred forty-two thousand, four hundred twenty-one".