21212211100 has 36 divisors (see below), whose sum is σ = 46041738904. Its totient is φ = 8482812480.

The previous prime is 21212211073. The next prime is 21212211103. The reversal of 21212211100 is 111221212.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21212211103) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 424642 + ... + 471958.

Almost surely, 2^21212211100 is an apocalyptic number.

21212211100 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21212211100 is an abundant number, since it is smaller than the sum of its proper divisors (24829527804).

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

21212211100 is a wasteful number, since it uses less digits than its factorization.

21212211100 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 51814 (or 51807 counting only the distinct ones).

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

Adding to 21212211100 its reverse (111221212), we get a palindrome (21323432312).

The spelling of 21212211100 in words is "twenty-one billion, two hundred twelve million, two hundred eleven thousand, one hundred".