212211110021221 has 4 divisors (see below), whose sum is σ = 212211538454412. Its totient is φ = 212210681588032.

The previous prime is 212211110021189. The next prime is 212211110021227. The reversal of 212211110021221 is 122120011112212.

It is a happy number.

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 122011244056900 + 90199865964321 = 11045870^2 + 9497361^2 .

It is a cyclic number.

It is not a de Polignac number, because 212211110021221 - 2⁵ = 212211110021189 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 (212211110021227) 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, 213472756 + ... + 214464541.

It is an arithmetic number, because the mean of its divisors is an integer number (53052884613603).

Almost surely, 2^{212211110021221} is an apocalyptic number.

It is an amenable number.

212211110021221 is a deficient number, since it is larger than the sum of its proper divisors (428433191).

212211110021221 is an equidigital number, since it uses as much as digits as its factorization.

212211110021221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 428433190.

The product of its (nonzero) digits is 64, while the sum is 19.

Adding to 212211110021221 its reverse (122120011112212), we get a palindrome (334331121133433).

The spelling of 212211110021221 in words is "two hundred twelve trillion, two hundred eleven billion, one hundred ten million, twenty-one thousand, two hundred twenty-one".