212308909 has 2 divisors, whose sum is σ = 212308910. Its totient is φ = 212308908.

The previous prime is 212308879. The next prime is 212308919. The reversal of 212308909 is 909803212.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 188980009 + 23328900 = 13747^2 + 4830^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-212308909 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (212308919) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 106154454 + 106154455.

It is an arithmetic number, because the mean of its divisors is an integer number (106154455).

Almost surely, 2^212308909 is an apocalyptic number.

It is an amenable number.

212308909 is a deficient number, since it is larger than the sum of its proper divisors (1).

212308909 is an equidigital number, since it uses as much as digits as its factorization.

212308909 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 7776, while the sum is 34.

The square root of 212308909 is about 14570.8238957171. The cubic root of 212308909 is about 596.5626686750.

The spelling of 212308909 in words is "two hundred twelve million, three hundred eight thousand, nine hundred nine".