20121220309 has 2 divisors, whose sum is σ = 20121220310. Its totient is φ = 20121220308.

The previous prime is 20121220291. The next prime is 20121220319. The reversal of 20121220309 is 90302212102.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 19855628100 + 265592209 = 140910^2 + 16297^2 .

It is a cyclic number.

It is not a de Polignac number, because 20121220309 - 2⁷ = 20121220181 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 20121220309.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20121220319) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10060610154 + 10060610155.

It is an arithmetic number, because the mean of its divisors is an integer number (10060610155).

Almost surely, 2^20121220309 is an apocalyptic number.

It is an amenable number.

20121220309 is a deficient number, since it is larger than the sum of its proper divisors (1).

20121220309 is an equidigital number, since it uses as much as digits as its factorization.

20121220309 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 432, while the sum is 22.

The spelling of 20121220309 in words is "twenty billion, one hundred twenty-one million, two hundred twenty thousand, three hundred nine".