20001212121021 has 4 divisors (see below), whose sum is σ = 26668282828032. Its totient is φ = 13334141414012.

The previous prime is 20001212121017. The next prime is 20001212121043. The reversal of 20001212121021 is 12012121210002.

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 20001212121021 - 2² = 20001212121017 is a prime.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20001212121091) 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, 3333535353501 + ... + 3333535353506.

It is an arithmetic number, because the mean of its divisors is an integer number (6667070707008).

Almost surely, 2^{20001212121021} is an apocalyptic number.

It is an amenable number.

20001212121021 is a deficient number, since it is larger than the sum of its proper divisors (6667070707011).

20001212121021 is an equidigital number, since it uses as much as digits as its factorization.

20001212121021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6667070707010.

The product of its (nonzero) digits is 32, while the sum is 15.

Adding to 20001212121021 its reverse (12012121210002), we get a palindrome (32013333331023).

The spelling of 20001212121021 in words is "twenty trillion, one billion, two hundred twelve million, one hundred twenty-one thousand, twenty-one".