20021122021 has 2 divisors, whose sum is σ = 20021122022.
Its totient is φ = 20021122020.
The previous prime is 20021122019. The next prime is 20021122061. The reversal of 20021122021 is 12022112002.
Adding to 20021122021 its reverse (12022112002), we get a palindrome (32043234023).
It is a happy number.
It is a weak prime.
It can be written as a sum of positive squares in only one way, i.e., 16638420100 + 3382701921 = 128990^2 + 58161^2
It is a cyclic number.
It is not a de Polignac number, because 20021122021 - 21 = 20021122019 is a prime.
It is a super-2 number, since 2×200211220212 (a number of 21 digits) contains 22 as substring.
Together with 20021122019, it forms a pair of twin primes.
It is a junction number, because it is equal to n+sod(n) for n = 20021121992 and 20021122010.
It is a congruent number.
It is not a weakly prime, because it can be changed into another prime (20021122001) 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 as a sum of consecutive naturals, namely, 10010561010 + 10010561011.
It is an arithmetic number, because the mean of its divisors is an integer number (10010561011).
Almost surely, 220021122021 is an apocalyptic number.
It is an amenable number.
20021122021 is a deficient number, since it is larger than the sum of its proper divisors (1).
20021122021 is an equidigital number, since it uses as much as digits as its factorization.
20021122021 is an odious number, because the sum of its binary digits is odd.
The product of its (nonzero) digits is 32, while the sum is 13.
The spelling of 20021122021 in words is "twenty billion, twenty-one million, one hundred twenty-two thousand, twenty-one".