20001210012221 has 4 divisors (see below), whose sum is σ = 20001727185372. Its totient is φ = 20000692839072.

The previous prime is 20001210012209. The next prime is 20001210012247. The reversal of 20001210012221 is 12221001210002.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 10191347527321 + 9809862484900 = 3192389^2 + 3132070^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20001210012221 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 20001210012196 and 20001210012205.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20001210011221) 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, 258528560 + ... + 258605913.

It is an arithmetic number, because the mean of its divisors is an integer number (5000431796343).

Almost surely, 2^{20001210012221} is an apocalyptic number.

It is an amenable number.

20001210012221 is a deficient number, since it is larger than the sum of its proper divisors (517173151).

20001210012221 is an equidigital number, since it uses as much as digits as its factorization.

20001210012221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 517173150.

The product of its (nonzero) digits is 32, while the sum is 14.

Adding to 20001210012221 its reverse (12221001210002), we get a palindrome (32222211222223).

The spelling of 20001210012221 in words is "twenty trillion, one billion, two hundred ten million, twelve thousand, two hundred twenty-one".