20021220121 has 24 divisors (see below), whose sum is σ = 23421655680. Its totient is φ = 17064304992.

The previous prime is 20021220119. The next prime is 20021220133. The reversal of 20021220121 is 12102212002.

It is a happy number.

It is not a de Polignac number, because 20021220121 - 2¹ = 20021220119 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20021220101) 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 23 ways as a sum of consecutive naturals, for example, 8400496 + ... + 8402878.

It is an arithmetic number, because the mean of its divisors is an integer number (975902320).

Almost surely, 2^20021220121 is an apocalyptic number.

It is an amenable number.

20021220121 is a deficient number, since it is larger than the sum of its proper divisors (3400435559).

20021220121 is a wasteful number, since it uses less digits than its factorization.

20021220121 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3293 (or 3286 counting only the distinct ones).

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

Adding to 20021220121 its reverse (12102212002), we get a palindrome (32123432123).

The spelling of 20021220121 in words is "twenty billion, twenty-one million, two hundred twenty thousand, one hundred twenty-one".