20021222021 has 4 divisors (see below), whose sum is σ = 20219452044. Its totient is φ = 19822992000.

The previous prime is 20021222017. The next prime is 20021222041. The reversal of 20021222021 is 12022212002.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 16684888900 + 3336333121 = 129170^2 + 57761^2 .

It is a cyclic number.

It is not a de Polignac number, because 20021222021 - 2² = 20021222017 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 20021221987 and 20021222005.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20021222041) 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, 99114860 + ... + 99115061.

It is an arithmetic number, because the mean of its divisors is an integer number (5054863011).

Almost surely, 2^20021222021 is an apocalyptic number.

It is an amenable number.

20021222021 is a deficient number, since it is larger than the sum of its proper divisors (198230023).

20021222021 is a wasteful number, since it uses less digits than its factorization.

20021222021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 198230022.

The product of its (nonzero) digits is 64, while the sum is 14.

Adding to 20021222021 its reverse (12022212002), we get a palindrome (32043434023).

The spelling of 20021222021 in words is "twenty billion, twenty-one million, two hundred twenty-two thousand, twenty-one".