20101211221 has 16 divisors (see below), whose sum is σ = 25088410368. Its totient is φ = 15680246400.

The previous prime is 20101211189. The next prime is 20101211227. The reversal of 20101211221 is 12211210102.

It is not a de Polignac number, because 20101211221 - 2⁵ = 20101211189 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (13).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20101211227) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1549120 + ... + 1562041.

It is an arithmetic number, because the mean of its divisors is an integer number (1568025648).

Almost surely, 2^20101211221 is an apocalyptic number.

It is an amenable number.

20101211221 is a deficient number, since it is larger than the sum of its proper divisors (4987199147).

20101211221 is a wasteful number, since it uses less digits than its factorization.

20101211221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3111252.

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

Adding to 20101211221 its reverse (12211210102), we get a palindrome (32312421323).

The spelling of 20101211221 in words is "twenty billion, one hundred one million, two hundred eleven thousand, two hundred twenty-one".