20041221209 has 2 divisors, whose sum is σ = 20041221210. Its totient is φ = 20041221208.

The previous prime is 20041221121. The next prime is 20041221227. The reversal of 20041221209 is 90212214002.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 19419816025 + 621405184 = 139355^2 + 24928^2 .

It is a cyclic number.

It is not a de Polignac number, because 20041221209 - 2¹² = 20041217113 is a prime.

It is not a weakly prime, because it can be changed into another prime (20041221509) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10020610604 + 10020610605.

It is an arithmetic number, because the mean of its divisors is an integer number (10020610605).

Almost surely, 2^20041221209 is an apocalyptic number.

It is an amenable number.

20041221209 is a deficient number, since it is larger than the sum of its proper divisors (1).

20041221209 is an equidigital number, since it uses as much as digits as its factorization.

20041221209 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 576, while the sum is 23.

The spelling of 20041221209 in words is "twenty billion, forty-one million, two hundred twenty-one thousand, two hundred nine".