20121221220001 has 16 divisors (see below), whose sum is σ = 21974789726208. Its totient is φ = 18271716699600.

The previous prime is 20121221219999. The next prime is 20121221220017. The reversal of 20121221220001 is 10002212212102.

It is a happy number.

It is a cyclic number.

It is not a de Polignac number, because 20121221220001 - 2¹ = 20121221219999 is a prime.

It is not an unprimeable number, because it can be changed into a prime (20121221223001) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 156118656 + ... + 156247486.

It is an arithmetic number, because the mean of its divisors is an integer number (1373424357888).

Almost surely, 2^{20121221220001} is an apocalyptic number.

It is an amenable number.

20121221220001 is a deficient number, since it is larger than the sum of its proper divisors (1853568506207).

20121221220001 is a wasteful number, since it uses less digits than its factorization.

20121221220001 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 144492.

The product of its (nonzero) digits is 64, while the sum is 16.

Adding to 20121221220001 its reverse (10002212212102), we get a palindrome (30123433432103).

The spelling of 20121221220001 in words is "twenty trillion, one hundred twenty-one billion, two hundred twenty-one million, two hundred twenty thousand, one".