21120112220100 has 144 divisors (see below), whose sum is σ = 63848179704960. Its totient is φ = 5380078668800.

The previous prime is 21120112220099. The next prime is 21120112220107. The reversal of 21120112220100 is 102221102112.

It is a Harshad number since it is a multiple of its sum of digits (15).

It is a self number, because there is not a number n which added to its sum of digits gives 21120112220100.

It is not an unprimeable number, because it can be changed into a prime (21120112220107) 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, 3239806 + ... + 7261994.

It is an arithmetic number, because the mean of its divisors is an integer number (443390136840).

Almost surely, 2^{21120112220100} is an apocalyptic number.

21120112220100 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 21120112220100, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (31924089852480).

21120112220100 is an abundant number, since it is smaller than the sum of its proper divisors (42728067484860).

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

21120112220100 is a wasteful number, since it uses less digits than its factorization.

21120112220100 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4022990 (or 4022983 counting only the distinct ones).

The product of its (nonzero) digits is 32, while the sum is 15.

Adding to 21120112220100 its reverse (102221102112), we get a palindrome (21222333322212).

The spelling of 21120112220100 in words is "twenty-one trillion, one hundred twenty billion, one hundred twelve million, two hundred twenty thousand, one hundred".