212121222021 has 12 divisors (see below), whose sum is σ = 319718943648. Its totient is φ = 135265706664.

The previous prime is 212121221999. The next prime is 212121222029. The reversal of 212121222021 is 120222121212.

It is a happy number.

212121222021 is a `hidden beast` number, since 212 + 1 + 212 + 220 + 21 = 666.

It is not a de Polignac number, because 212121222021 - 2¹⁵ = 212121189253 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 212121221985 and 212121222003.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (212121222029) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 512369895 + ... + 512370308.

It is an arithmetic number, because the mean of its divisors is an integer number (26643245304).

Almost surely, 2^212121222021 is an apocalyptic number.

It is an amenable number.

212121222021 is a deficient number, since it is larger than the sum of its proper divisors (107597721627).

212121222021 is a wasteful number, since it uses less digits than its factorization.

212121222021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1024740232 (or 1024740229 counting only the distinct ones).

The product of its (nonzero) digits is 128, while the sum is 18.

Adding to 212121222021 its reverse (120222121212), we get a palindrome (332343343233).

The spelling of 212121222021 in words is "two hundred twelve billion, one hundred twenty-one million, two hundred twenty-two thousand, twenty-one".