212040221 has 2 divisors, whose sum is σ = 212040222. Its totient is φ = 212040220.

The previous prime is 212040203. The next prime is 212040223. The reversal of 212040221 is 122040212.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 177688900 + 34351321 = 13330^2 + 5861^2 .

It is a cyclic number.

It is not a de Polignac number, because 212040221 - 2¹⁰ = 212039197 is a prime.

It is a super-2 number, since 2×212040221² = 89922110643457682, which contains 22 as substring.

It is a Sophie Germain prime.

Together with 212040223, it forms a pair of twin primes.

It is a Chen prime.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 212040196 and 212040205.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (212040223) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 106020110 + 106020111.

It is an arithmetic number, because the mean of its divisors is an integer number (106020111).

Almost surely, 2^212040221 is an apocalyptic number.

It is an amenable number.

212040221 is a deficient number, since it is larger than the sum of its proper divisors (1).

212040221 is an equidigital number, since it uses as much as digits as its factorization.

212040221 is an odious number, because the sum of its binary digits is odd.

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

The square root of 212040221 is about 14561.6009078672. The cubic root of 212040221 is about 596.3109020443.

Adding to 212040221 its reverse (122040212), we get a palindrome (334080433).

Subtracting from 212040221 its reverse (122040212), we obtain a palindrome (90000009).

The spelling of 212040221 in words is "two hundred twelve million, forty thousand, two hundred twenty-one".