20001201209909 has 2 divisors, whose sum is σ = 20001201209910. Its totient is φ = 20001201209908.

The previous prime is 20001201209851. The next prime is 20001201209911. The reversal of 20001201209909 is 90990210210002.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 18213305967025 + 1787895242884 = 4267705^2 + 1337122^2 .

It is a cyclic number.

It is not a de Polignac number, because 20001201209909 - 2²⁸ = 20000932774453 is a prime.

Together with 20001201209911, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20001201209959) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10000600604954 + 10000600604955.

It is an arithmetic number, because the mean of its divisors is an integer number (10000600604955).

Almost surely, 2^{20001201209909} is an apocalyptic number.

It is an amenable number.

20001201209909 is a deficient number, since it is larger than the sum of its proper divisors (1).

20001201209909 is an equidigital number, since it uses as much as digits as its factorization.

20001201209909 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 5832, while the sum is 35.

The spelling of 20001201209909 in words is "twenty trillion, one billion, two hundred one million, two hundred nine thousand, nine hundred nine".