20121201209 has 2 divisors, whose sum is σ = 20121201210. Its totient is φ = 20121201208.

The previous prime is 20121201203. The next prime is 20121201223. The reversal of 20121201209 is 90210212102.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 10359168400 + 9762032809 = 101780^2 + 98803^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20121201209 is a prime.

It is not a weakly prime, because it can be changed into another prime (20121201203) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10060600604 + 10060600605.

It is an arithmetic number, because the mean of its divisors is an integer number (10060600605).

Almost surely, 2^20121201209 is an apocalyptic number.

It is an amenable number.

20121201209 is a deficient number, since it is larger than the sum of its proper divisors (1).

20121201209 is an equidigital number, since it uses as much as digits as its factorization.

20121201209 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 144, while the sum is 20.

The spelling of 20121201209 in words is "twenty billion, one hundred twenty-one million, two hundred one thousand, two hundred nine".