20000121210021 has 4 divisors (see below), whose sum is σ = 26666828280032. Its totient is φ = 13333414140012.

The previous prime is 20000121209987. The next prime is 20000121210073. The reversal of 20000121210021 is 12001212100002.

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 not a de Polignac number, because 20000121210021 - 2¹⁰ = 20000121208997 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 20000121209979 and 20000121210006.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20002121210021) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3333353535001 + ... + 3333353535006.

It is an arithmetic number, because the mean of its divisors is an integer number (6666707070008).

Almost surely, 2^{20000121210021} is an apocalyptic number.

It is an amenable number.

20000121210021 is a deficient number, since it is larger than the sum of its proper divisors (6666707070011).

20000121210021 is an equidigital number, since it uses as much as digits as its factorization.

20000121210021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6666707070010.

The product of its (nonzero) digits is 16, while the sum is 12.

Adding to 20000121210021 its reverse (12001212100002), we get a palindrome (32001333310023).

The spelling of 20000121210021 in words is "twenty trillion, one hundred twenty-one million, two hundred ten thousand, twenty-one".