21100021120 has 128 divisors (see below), whose sum is σ = 51114240000. Its totient is φ = 8328388608.

The previous prime is 21100021109. The next prime is 21100021157. The reversal of 21100021120 is 2112000112.

It is a tau number, because it is divible by the number of its divisors (128).

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

It is a junction number, because it is equal to n+sod(n) for n = 21100021097 and 21100021106.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 16496641 + ... + 16497919.

It is an arithmetic number, because the mean of its divisors is an integer number (399330000).

Almost surely, 2^21100021120 is an apocalyptic number.

21100021120 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 21100021120, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (25557120000).

21100021120 is an abundant number, since it is smaller than the sum of its proper divisors (30014218880).

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

21100021120 is a wasteful number, since it uses less digits than its factorization.

21100021120 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1620 (or 1608 counting only the distinct ones).

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

Adding to 21100021120 its reverse (2112000112), we get a palindrome (23212021232).

The spelling of 21100021120 in words is "twenty-one billion, one hundred million, twenty-one thousand, one hundred twenty".