20121220001221 has 4 divisors (see below), whose sum is σ = 20996055653472. Its totient is φ = 19246384348972.

The previous prime is 20121220001167. The next prime is 20121220001269. The reversal of 20121220001221 is 12210002212102.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 20121220001221 - 2⁷ = 20121220001093 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 20121220001195 and 20121220001204.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20121220001291) 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 in 3 ways as a sum of consecutive naturals, for example, 437417826091 + ... + 437417826136.

It is an arithmetic number, because the mean of its divisors is an integer number (5249013913368).

Almost surely, 2^{20121220001221} is an apocalyptic number.

It is an amenable number.

20121220001221 is a deficient number, since it is larger than the sum of its proper divisors (874835652251).

20121220001221 is an equidigital number, since it uses as much as digits as its factorization.

20121220001221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 874835652250.

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

Adding to 20121220001221 its reverse (12210002212102), we get a palindrome (32331222213323).

The spelling of 20121220001221 in words is "twenty trillion, one hundred twenty-one billion, two hundred twenty million, one thousand, two hundred twenty-one".