201221102009 has 2 divisors, whose sum is σ = 201221102010. Its totient is φ = 201221102008.

The previous prime is 201221101951. The next prime is 201221102053. The reversal of 201221102009 is 900201122102.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 101509146025 + 99711955984 = 318605^2 + 315772^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-201221102009 is a prime.

It is not a weakly prime, because it can be changed into another prime (201221102309) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 100610551004 + 100610551005.

It is an arithmetic number, because the mean of its divisors is an integer number (100610551005).

Almost surely, 2^201221102009 is an apocalyptic number.

It is an amenable number.

201221102009 is a deficient number, since it is larger than the sum of its proper divisors (1).

201221102009 is an equidigital number, since it uses as much as digits as its factorization.

201221102009 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 201221102009 in words is "two hundred one billion, two hundred twenty-one million, one hundred two thousand, nine".