20021220212121 has 16 divisors (see below), whose sum is σ = 30067382969920. Its totient is φ = 13164637946400.

The previous prime is 20021220212113. The next prime is 20021220212171. The reversal of 20021220212121 is 12121202212002.

It is a happy number.

20021220212121 is a `hidden beast` number, since 200 + 21 + 220 + 212 + 12 + 1 = 666.

It is not a de Polignac number, because 20021220212121 - 2³ = 20021220212113 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 20021220212094 and 20021220212103.

It is not an unprimeable number, because it can be changed into a prime (20021220212101) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 5078947855 + ... + 5078951796.

It is an arithmetic number, because the mean of its divisors is an integer number (1879211435620).

Almost surely, 2^{20021220212121} is an apocalyptic number.

It is an amenable number.

20021220212121 is a deficient number, since it is larger than the sum of its proper divisors (10046162757799).

20021220212121 is a wasteful number, since it uses less digits than its factorization.

20021220212121 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10157899733 (or 10157899727 counting only the distinct ones).

The product of its (nonzero) digits is 128, while the sum is 18.

Adding to 20021220212121 its reverse (12121202212002), we get a palindrome (32142422424123).

The spelling of 20021220212121 in words is "twenty trillion, twenty-one billion, two hundred twenty million, two hundred twelve thousand, one hundred twenty-one".