212122112221 has 4 divisors (see below), whose sum is σ = 213348251772. Its totient is φ = 210895972672.

The previous prime is 212122112201. The next prime is 212122112239. The reversal of 212122112221 is 122211221212.

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 142592332996 + 69529779225 = 377614^2 + 263685^2 .

It is a cyclic number.

It is not a de Polignac number, because 212122112221 - 2¹¹ = 212122110173 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 (212122112201) 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, 613069516 + ... + 613069861.

It is an arithmetic number, because the mean of its divisors is an integer number (53337062943).

Almost surely, 2^212122112221 is an apocalyptic number.

It is an amenable number.

212122112221 is a deficient number, since it is larger than the sum of its proper divisors (1226139551).

212122112221 is a wasteful number, since it uses less digits than its factorization.

212122112221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1226139550.

The product of its digits is 128, while the sum is 19.

Adding to 212122112221 its reverse (122211221212), we get a palindrome (334333333433).

The spelling of 212122112221 in words is "two hundred twelve billion, one hundred twenty-two million, one hundred twelve thousand, two hundred twenty-one".