21102111100 has 144 divisors (see below), whose sum is σ = 53371584000. Its totient is φ = 7092184320.

The previous prime is 21102111097. The next prime is 21102111103. The reversal of 21102111100 is 111120112.

It is an interprime number because it is at equal distance from previous prime (21102111097) and next prime (21102111103).

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 (21102111103) 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, 24738274 + ... + 24739126.

It is an arithmetic number, because the mean of its divisors is an integer number (370636000).

Almost surely, 2^21102111100 is an apocalyptic number.

21102111100 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 21102111100, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (26685792000).

21102111100 is an abundant number, since it is smaller than the sum of its proper divisors (32269472900).

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

21102111100 is a wasteful number, since it uses less digits than its factorization.

21102111100 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1532 (or 1525 counting only the distinct ones).

The product of its (nonzero) digits is 4, while the sum is 10.

Adding to 21102111100 its reverse (111120112), we get a palindrome (21213231212).

The spelling of 21102111100 in words is "twenty-one billion, one hundred two million, one hundred eleven thousand, one hundred".