212212220021 has 4 divisors (see below), whose sum is σ = 212216264172. Its totient is φ = 212208175872.

The previous prime is 212212219981. The next prime is 212212220023. The reversal of 212212220021 is 120022212212.

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 175774755025 + 36437464996 = 419255^2 + 190886^2 .

It is a cyclic number.

It is not a de Polignac number, because 212212220021 - 2³⁰ = 211138478197 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 (212212220023) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1942316 + ... + 2048661.

It is an arithmetic number, because the mean of its divisors is an integer number (53054066043).

Almost surely, 2^212212220021 is an apocalyptic number.

It is an amenable number.

212212220021 is a deficient number, since it is larger than the sum of its proper divisors (4044151).

212212220021 is an equidigital number, since it uses as much as digits as its factorization.

212212220021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4044150.

The product of its (nonzero) digits is 128, while the sum is 17.

Adding to 212212220021 its reverse (120022212212), we get a palindrome (332234432233).

The spelling of 212212220021 in words is "two hundred twelve billion, two hundred twelve million, two hundred twenty thousand, twenty-one".