20111210221 has 4 divisors (see below), whose sum is σ = 20121725052. Its totient is φ = 20100695392.

The previous prime is 20111210131. The next prime is 20111210233. The reversal of 20111210221 is 12201211102.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 12201211102 = 2 ⋅6100605551.

It can be written as a sum of positive squares in 2 ways, for example, as 19213009321 + 898200900 = 138611^2 + 29970^2 .

It is a cyclic number.

It is not a de Polignac number, because 20111210221 - 2⁹ = 20111209709 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20111210321) 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, 5254546 + ... + 5258371.

It is an arithmetic number, because the mean of its divisors is an integer number (5030431263).

Almost surely, 2^20111210221 is an apocalyptic number.

It is an amenable number.

20111210221 is a deficient number, since it is larger than the sum of its proper divisors (10514831).

20111210221 is a wasteful number, since it uses less digits than its factorization.

20111210221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10514830.

The product of its (nonzero) digits is 16, while the sum is 13.

Adding to 20111210221 its reverse (12201211102), we get a palindrome (32312421323).

The spelling of 20111210221 in words is "twenty billion, one hundred eleven million, two hundred ten thousand, two hundred twenty-one".