20001222121 has 4 divisors (see below), whose sum is σ = 20001991312. Its totient is φ = 20000452932.

The previous prime is 20001222113. The next prime is 20001222149. The reversal of 20001222121 is 12122210002.

It is a happy number.

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 20001222121 - 2³ = 20001222113 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20001222161) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 344175 + ... + 398068.

It is an arithmetic number, because the mean of its divisors is an integer number (5000497828).

Almost surely, 2^20001222121 is an apocalyptic number.

It is an amenable number.

20001222121 is a deficient number, since it is larger than the sum of its proper divisors (769191).

20001222121 is an equidigital number, since it uses as much as digits as its factorization.

20001222121 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 769190.

The product of its (nonzero) digits is 32, while the sum is 13.

Adding to 20001222121 its reverse (12122210002), we get a palindrome (32123432123).

The spelling of 20001222121 in words is "twenty billion, one million, two hundred twenty-two thousand, one hundred twenty-one".