21220110100 has 144 divisors (see below), whose sum is σ = 55947669120. Its totient is φ = 6823872000.

The previous prime is 21220110089. The next prime is 21220110103. The reversal of 21220110100 is 101102212.

It is a super-2 number, since 2×21220110100² (a number of 21 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (10).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21220110103) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 1335402 + ... + 1351198.

It is an arithmetic number, because the mean of its divisors is an integer number (388525480).

Almost surely, 2^21220110100 is an apocalyptic number.

21220110100 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21220110100, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (27973834560).

21220110100 is an abundant number, since it is smaller than the sum of its proper divisors (34727559020).

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

21220110100 is a wasteful number, since it uses less digits than its factorization.

21220110100 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 15938 (or 15931 counting only the distinct ones).

The product of its (nonzero) digits is 8, while the sum is 10.

Adding to 21220110100 its reverse (101102212), we get a palindrome (21321212312).

The spelling of 21220110100 in words is "twenty-one billion, two hundred twenty million, one hundred ten thousand, one hundred".