212222021 has 6 divisors (see below), whose sum is σ = 233268966. Its totient is φ = 192929000.

The previous prime is 212222011. The next prime is 212222051. The reversal of 212222021 is 120222212.

It can be written as a sum of positive squares in only one way, i.e., 119793025 + 92428996 = 10945^2 + 9614^2 .

It is not a de Polignac number, because 212222021 - 2¹⁰ = 212220997 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 212221987 and 212222005.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (212222011) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 876830 + ... + 877071.

It is an arithmetic number, because the mean of its divisors is an integer number (38878161).

Almost surely, 2^212222021 is an apocalyptic number.

It is an amenable number.

212222021 is a deficient number, since it is larger than the sum of its proper divisors (21046945).

212222021 is a wasteful number, since it uses less digits than its factorization.

212222021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1753923 (or 1753912 counting only the distinct ones).

The product of its (nonzero) digits is 64, while the sum is 14.

The square root of 212222021 is about 14567.8420158924. The cubic root of 212222021 is about 596.4812759375.

Adding to 212222021 its reverse (120222212), we get a palindrome (332444233).

The spelling of 212222021 in words is "two hundred twelve million, two hundred twenty-two thousand, twenty-one".