212547221 has 2 divisors, whose sum is σ = 212547222. Its totient is φ = 212547220.

The previous prime is 212547217. The next prime is 212547227. The reversal of 212547221 is 122745212.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 152794321 + 59752900 = 12361^2 + 7730^2 .

It is a cyclic number.

It is not a de Polignac number, because 212547221 - 2² = 212547217 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (212547227) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 106273610 + 106273611.

It is an arithmetic number, because the mean of its divisors is an integer number (106273611).

Almost surely, 2^212547221 is an apocalyptic number.

It is an amenable number.

212547221 is a deficient number, since it is larger than the sum of its proper divisors (1).

212547221 is an equidigital number, since it uses as much as digits as its factorization.

212547221 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 2240, while the sum is 26.

The square root of 212547221 is about 14578.9993140819. Note that the first 3 decimals coincide. The cubic root of 212547221 is about 596.7857946270.

The spelling of 212547221 in words is "two hundred twelve million, five hundred forty-seven thousand, two hundred twenty-one".