212021111221 has 4 divisors (see below), whose sum is σ = 212689947852. Its totient is φ = 211352274592.

The previous prime is 212021111201. The next prime is 212021111251. The reversal of 212021111221 is 122111120212.

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 54610548721 + 157410562500 = 233689^2 + 396750^2 .

It is a cyclic number.

It is not a de Polignac number, because 212021111221 - 2⁵ = 212021111189 is a prime.

It is a super-2 number, since 2×212021111221² (a number of 23 digits) contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 212021111195 and 212021111204.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (212021111201) 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, 334417840 + ... + 334418473.

It is an arithmetic number, because the mean of its divisors is an integer number (53172486963).

Almost surely, 2^212021111221 is an apocalyptic number.

It is an amenable number.

212021111221 is a deficient number, since it is larger than the sum of its proper divisors (668836631).

212021111221 is an equidigital number, since it uses as much as digits as its factorization.

212021111221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 668836630.

The product of its (nonzero) digits is 32, while the sum is 16.

Adding to 212021111221 its reverse (122111120212), we get a palindrome (334132231433).

The spelling of 212021111221 in words is "two hundred twelve billion, twenty-one million, one hundred eleven thousand, two hundred twenty-one".