20011221211 has 4 divisors (see below), whose sum is σ = 21064443400.
Its totient is φ = 18957999024.
The previous prime is 20011221193. The next prime is 20011221239. The reversal of 20011221211 is 11212211002.
Adding to 20011221211 its reverse (11212211002), we get a palindrome (31223432213).
It is a semiprime because it is the product of two primes.
It is a cyclic number.
It is not a de Polignac number, because 20011221211 - 233 = 11421286619 is a prime.
It is a Duffinian number.
It is a junction number, because it is equal to n+sod(n) for n = 20011221191 and 20011221200.
It is not an unprimeable number, because it can be changed into a prime (20011221311) by changing a digit.
It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 526611066 + ... + 526611103.
It is an arithmetic number, because the mean of its divisors is an integer number (5266110850).
Almost surely, 220011221211 is an apocalyptic number.
20011221211 is a deficient number, since it is larger than the sum of its proper divisors (1053222189).
20011221211 is a wasteful number, since it uses less digits than its factorization.
20011221211 is an evil number, because the sum of its binary digits is even.
The sum of its prime factors is 1053222188.
The product of its (nonzero) digits is 16, while the sum is 13.
The spelling of 20011221211 in words is "twenty billion, eleven million, two hundred twenty-one thousand, two hundred eleven".