21212121110 has 16 divisors (see below), whose sum is σ = 40427807616. Its totient is φ = 7985739648.

The previous prime is 21212121109. The next prime is 21212121157. The reversal of 21212121110 is 1112121212.

It is a Curzon number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 62388422 + ... + 62388761.

It is an arithmetic number, because the mean of its divisors is an integer number (2526737976).

Almost surely, 2^21212121110 is an apocalyptic number.

21212121110 is a deficient number, since it is larger than the sum of its proper divisors (19215686506).

21212121110 is a wasteful number, since it uses less digits than its factorization.

21212121110 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 124777207.

The product of its (nonzero) digits is 16, while the sum is 14.

Adding to 21212121110 its reverse (1112121212), we get a palindrome (22324242322).

The spelling of 21212121110 in words is "twenty-one billion, two hundred twelve million, one hundred twenty-one thousand, one hundred ten".