212130221 has 4 divisors (see below), whose sum is σ = 216132732. Its totient is φ = 208127712.

The previous prime is 212130161. The next prime is 212130229. The reversal of 212130221 is 122031212.

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 168636196 + 43494025 = 12986^2 + 6595^2 .

It is a cyclic number.

It is not a de Polignac number, because 212130221 - 2¹⁸ = 211868077 is a prime.

It is a Duffinian number.

212130221 is a modest number, since divided by 130221 gives 212 as remainder.

It is a junction number, because it is equal to n+sod(n) for n = 212130196 and 212130205.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (212130229) 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, 2001176 + ... + 2001281.

It is an arithmetic number, because the mean of its divisors is an integer number (54033183).

Almost surely, 2^212130221 is an apocalyptic number.

It is an amenable number.

212130221 is a deficient number, since it is larger than the sum of its proper divisors (4002511).

212130221 is an equidigital number, since it uses as much as digits as its factorization.

212130221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4002510.

The product of its (nonzero) digits is 48, while the sum is 14.

The square root of 212130221 is about 14564.6908995694. The cubic root of 212130221 is about 596.3952577224.

Adding to 212130221 its reverse (122031212), we get a palindrome (334161433).

Subtracting from 212130221 its reverse (122031212), we obtain a palindrome (90099009).

The spelling of 212130221 in words is "two hundred twelve million, one hundred thirty thousand, two hundred twenty-one".