20121221201028 has 24 divisors (see below), whose sum is σ = 48094626286560. Its totient is φ = 6543486569280.

The previous prime is 20121221201027. The next prime is 20121221201051. The reversal of 20121221201028 is 82010212212102.

It is a junction number, because it is equal to n+sod(n) for n = 20121221200989 and 20121221201007.

It is not an unprimeable number, because it can be changed into a prime (20121221201027) 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 7 ways as a sum of consecutive naturals, for example, 20448395038 + ... + 20448396021.

It is an arithmetic number, because the mean of its divisors is an integer number (2003942761940).

Almost surely, 2^{20121221201028} is an apocalyptic number.

It is an amenable number.

20121221201028 is an abundant number, since it is smaller than the sum of its proper divisors (27973405085532).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

20121221201028 is a wasteful number, since it uses less digits than its factorization.

20121221201028 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 40896791107 (or 40896791105 counting only the distinct ones).

The product of its (nonzero) digits is 512, while the sum is 24.

The spelling of 20121221201028 in words is "twenty trillion, one hundred twenty-one billion, two hundred twenty-one million, two hundred one thousand, twenty-eight".