20021221200121 has 8 divisors (see below), whose sum is σ = 20064605985000. Its totient is φ = 19977855406080.

The previous prime is 20021221200109. The next prime is 20021221200137. The reversal of 20021221200121 is 12100212212002.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 221524600896 + 19799696599225 = 470664^2 + 4449685^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 20021221200121 - 2¹⁷ = 20021221069049 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 20021221200095 and 20021221200104.

It is not an unprimeable number, because it can be changed into a prime (20021221500121) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2635896 + ... + 6854953.

It is an arithmetic number, because the mean of its divisors is an integer number (2508075748125).

Almost surely, 2^{20021221200121} is an apocalyptic number.

It is an amenable number.

20021221200121 is a deficient number, since it is larger than the sum of its proper divisors (43384784879).

20021221200121 is an equidigital number, since it uses as much as digits as its factorization.

20021221200121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9495419.

The product of its (nonzero) digits is 64, while the sum is 16.

Adding to 20021221200121 its reverse (12100212212002), we get a palindrome (32121433412123).

The spelling of 20021221200121 in words is "twenty trillion, twenty-one billion, two hundred twenty-one million, two hundred thousand, one hundred twenty-one".