21001122222 has 16 divisors (see below), whose sum is σ = 42059089920. Its totient is φ = 6990899832.

The previous prime is 21001122179. The next prime is 21001122223. The reversal of 21001122222 is 22222110012.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21001122223) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2363758 + ... + 2372625.

It is an arithmetic number, because the mean of its divisors is an integer number (2628693120).

Almost surely, 2^21001122222 is an apocalyptic number.

21001122222 is an abundant number, since it is smaller than the sum of its proper divisors (21057967698).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21001122222 is a wasteful number, since it uses less digits than its factorization.

21001122222 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4737127.

The product of its (nonzero) digits is 64, while the sum is 15.

Adding to 21001122222 its reverse (22222110012), we get a palindrome (43223232234).

The spelling of 21001122222 in words is "twenty-one billion, one million, one hundred twenty-two thousand, two hundred twenty-two".