2111212221 has 16 divisors (see below), whose sum is σ = 2894293248. Its totient is φ = 1368057600.

The previous prime is 2111212219. The next prime is 2111212241. The reversal of 2111212221 is 1222121112.

It is not a de Polignac number, because 2111212221 - 2¹ = 2111212219 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 2111212221.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2111212211) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1665 + ... + 65001.

It is an arithmetic number, because the mean of its divisors is an integer number (180893328).

Almost surely, 2^2111212221 is an apocalyptic number.

It is an amenable number.

2111212221 is a deficient number, since it is larger than the sum of its proper divisors (783081027).

2111212221 is a wasteful number, since it uses less digits than its factorization.

2111212221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 63652.

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

The square root of 2111212221 is about 45947.9294528056. The cubic root of 2111212221 is about 1282.8541901787.

Adding to 2111212221 its reverse (1222121112), we get a palindrome (3333333333).

It can be divided in two parts, 21112 and 12221, that added together give a palindrome (33333).

The spelling of 2111212221 in words is "two billion, one hundred eleven million, two hundred twelve thousand, two hundred twenty-one".