20021021221221 has 6 divisors (see below), whose sum is σ = 28919252875110. Its totient is φ = 13347347480808.

The previous prime is 20021021221211. The next prime is 20021021221297. The reversal of 20021021221221 is 12212212012002.

It is a happy number.

20021021221221 is a `hidden beast` number, since 2 + 0 + 0 + 210 + 212 + 21 + 221 = 666.

It can be written as a sum of positive squares in only one way, i.e., 12577733180100 + 7443288041121 = 3546510^2 + 2728239^2 .

It is not a de Polignac number, because 20021021221221 - 2⁷ = 20021021221093 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 20021021221194 and 20021021221203.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20021021221211) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 1112278956726 + ... + 1112278956743.

It is an arithmetic number, because the mean of its divisors is an integer number (4819875479185).

Almost surely, 2^{20021021221221} is an apocalyptic number.

It is an amenable number.

20021021221221 is a deficient number, since it is larger than the sum of its proper divisors (8898231653889).

20021021221221 is a wasteful number, since it uses less digits than its factorization.

20021021221221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2224557913475 (or 2224557913472 counting only the distinct ones).

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

Adding to 20021021221221 its reverse (12212212012002), we get a palindrome (32233233233223).

The spelling of 20021021221221 in words is "twenty trillion, twenty-one billion, twenty-one million, two hundred twenty-one thousand, two hundred twenty-one".