20111212221 has 4 divisors (see below), whose sum is σ = 26814949632. Its totient is φ = 13407474812.

The previous prime is 20111212217. The next prime is 20111212229. The reversal of 20111212221 is 12221211102.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 20111212221 - 2² = 20111212217 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 20111212221.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20111212229) 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, 3351868701 + ... + 3351868706.

It is an arithmetic number, because the mean of its divisors is an integer number (6703737408).

Almost surely, 2^20111212221 is an apocalyptic number.

It is an amenable number.

20111212221 is a deficient number, since it is larger than the sum of its proper divisors (6703737411).

20111212221 is an equidigital number, since it uses as much as digits as its factorization.

20111212221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6703737410.

The product of its (nonzero) digits is 32, while the sum is 15.

Adding to 20111212221 its reverse (12221211102), we get a palindrome (32332423323).

The spelling of 20111212221 in words is "twenty billion, one hundred eleven million, two hundred twelve thousand, two hundred twenty-one".