21221101110 has 128 divisors (see below), whose sum is σ = 58110234624. Its totient is φ = 4909477760.

The previous prime is 21221101081. The next prime is 21221101169. The reversal of 21221101110 is 1110112212.

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, 3541537 + ... + 3547523.

It is an arithmetic number, because the mean of its divisors is an integer number (453986208).

Almost surely, 2^21221101110 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21221101110, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (29055117312).

21221101110 is an abundant number, since it is smaller than the sum of its proper divisors (36889133514).

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

21221101110 is a wasteful number, since it uses less digits than its factorization.

21221101110 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6498.

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

Adding to 21221101110 its reverse (1110112212), we get a palindrome (22331213322).

The spelling of 21221101110 in words is "twenty-one billion, two hundred twenty-one million, one hundred one thousand, one hundred ten".