20121021221021 has 4 divisors (see below), whose sum is σ = 22995452824032. Its totient is φ = 17246589618012.

The previous prime is 20121021221011. The next prime is 20121021221071. The reversal of 20121021221021 is 12012212012102.

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 20121021221021 - 2⁶ = 20121021220957 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20121021221011) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1437215801495 + ... + 1437215801508.

It is an arithmetic number, because the mean of its divisors is an integer number (5748863206008).

Almost surely, 2^{20121021221021} is an apocalyptic number.

It is an amenable number.

20121021221021 is a deficient number, since it is larger than the sum of its proper divisors (2874431603011).

20121021221021 is an equidigital number, since it uses as much as digits as its factorization.

20121021221021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2874431603010.

The product of its (nonzero) digits is 64, while the sum is 17.

Adding to 20121021221021 its reverse (12012212012102), we get a palindrome (32133233233123).

The spelling of 20121021221021 in words is "twenty trillion, one hundred twenty-one billion, twenty-one million, two hundred twenty-one thousand, twenty-one".