21212110110 has 128 divisors (see below), whose sum is σ = 52916613120. Its totient is φ = 5438822400.

The previous prime is 21212110109. The next prime is 21212110121. The reversal of 21212110110 is 1101121212.

It is a super-3 number, since 3×21212110110³ (a number of 32 digits) contains 333 as substring.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 24076870 + ... + 24077750.

It is an arithmetic number, because the mean of its divisors is an integer number (413411040).

Almost surely, 2^21212110110 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21212110110, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (26458306560).

21212110110 is an abundant number, since it is smaller than the sum of its proper divisors (31704503010).

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

21212110110 is a wasteful number, since it uses less digits than its factorization.

21212110110 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1234.

The product of its (nonzero) digits is 8, while the sum is 12.

Adding to 21212110110 its reverse (1101121212), we get a palindrome (22313231322).

The spelling of 21212110110 in words is "twenty-one billion, two hundred twelve million, one hundred ten thousand, one hundred ten".