20001201222221 has 4 divisors (see below), whose sum is σ = 20002809436092. Its totient is φ = 19999593008352.

The previous prime is 20001201222217. The next prime is 20001201222229. The reversal of 20001201222221 is 12222210210002.

It is a happy number.

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 460504746025 + 19540696476196 = 678605^2 + 4420486^2 .

It is a cyclic number.

It is not a de Polignac number, because 20001201222221 - 2² = 20001201222217 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 20001201222221.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20001201222229) 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, 804088280 + ... + 804113153.

It is an arithmetic number, because the mean of its divisors is an integer number (5000702359023).

Almost surely, 2^{20001201222221} is an apocalyptic number.

It is an amenable number.

20001201222221 is a deficient number, since it is larger than the sum of its proper divisors (1608213871).

20001201222221 is a wasteful number, since it uses less digits than its factorization.

20001201222221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1608213870.

The product of its (nonzero) digits is 128, while the sum is 17.

Adding to 20001201222221 its reverse (12222210210002), we get a palindrome (32223411432223).

The spelling of 20001201222221 in words is "twenty trillion, one billion, two hundred one million, two hundred twenty-two thousand, two hundred twenty-one".