20011121221 has 12 divisors (see below), whose sum is σ = 25068877932. Its totient is φ = 15832974528.

The previous prime is 20011121203. The next prime is 20011121237. The reversal of 20011121221 is 12212111002.

It can be written as a sum of positive squares in 2 ways, for example, as 1081488996 + 18929632225 = 32886^2 + 137585^2 .

It is not a de Polignac number, because 20011121221 - 2⁵ = 20011121189 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 (20611121221) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 15706680 + ... + 15707953.

It is an arithmetic number, because the mean of its divisors is an integer number (2089073161).

Almost surely, 2^20011121221 is an apocalyptic number.

It is an amenable number.

20011121221 is a deficient number, since it is larger than the sum of its proper divisors (5057756711).

20011121221 is a wasteful number, since it uses less digits than its factorization.

20011121221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 31414660 (or 31414653 counting only the distinct ones).

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

Adding to 20011121221 its reverse (12212111002), we get a palindrome (32223232223).

The spelling of 20011121221 in words is "twenty billion, eleven million, one hundred twenty-one thousand, two hundred twenty-one".