20011211021 has 2 divisors, whose sum is σ = 20011211022.
Its totient is φ = 20011211020.
The previous prime is 20011210993. The next prime is 20011211023. The reversal of 20011211021 is 12011211002.
Adding to 20011211021 its reverse (12011211002), we get a palindrome (32022422023).
It is a strong prime.
It can be written as a sum of positive squares in only one way, i.e., 19317942121 + 693268900 = 138989^2 + 26330^2
It is a cyclic number.
It is not a de Polignac number, because 20011211021 - 210 = 20011209997 is a prime.
Together with 20011211023, it forms a pair of twin primes.
It is a Chen prime.
It is a junction number, because it is equal to n+sod(n) for n = 20011210993 and 20011211011.
It is a congruent number.
It is not a weakly prime, because it can be changed into another prime (20011211023) by changing a digit.
It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10005605510 + 10005605511.
It is an arithmetic number, because the mean of its divisors is an integer number (10005605511).
Almost surely, 220011211021 is an apocalyptic number.
It is an amenable number.
20011211021 is a deficient number, since it is larger than the sum of its proper divisors (1).
20011211021 is an equidigital number, since it uses as much as digits as its factorization.
20011211021 is an odious number, because the sum of its binary digits is odd.
The product of its (nonzero) digits is 8, while the sum is 11.
The spelling of 20011211021 in words is "twenty billion, eleven million, two hundred eleven thousand, twenty-one".