212240309 has 2 divisors, whose sum is σ = 212240310. Its totient is φ = 212240308.

The previous prime is 212240267. The next prime is 212240321. The reversal of 212240309 is 903042212.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 198528100 + 13712209 = 14090^2 + 3703^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-212240309 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 (212243309) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 106120154 + 106120155.

It is an arithmetic number, because the mean of its divisors is an integer number (106120155).

Almost surely, 2^212240309 is an apocalyptic number.

It is an amenable number.

212240309 is a deficient number, since it is larger than the sum of its proper divisors (1).

212240309 is an equidigital number, since it uses as much as digits as its factorization.

212240309 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 864, while the sum is 23.

The square root of 212240309 is about 14568.4696862780. The cubic root of 212240309 is about 596.4984091521.

The spelling of 212240309 in words is "two hundred twelve million, two hundred forty thousand, three hundred nine".