21102100110 has 384 divisors, whose sum is σ = 70270986240. Its totient is φ = 4274684928.

The previous prime is 21102100109. The next prime is 21102100121. The reversal of 21102100110 is 1100120112.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (9).

It is a junction number, because it is equal to n+sod(n) for n = 21102100092 and 21102100101.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 191 ways as a sum of consecutive naturals, for example, 25151071 + ... + 25151909.

It is an arithmetic number, because the mean of its divisors is an integer number (182997360).

Almost surely, 2^21102100110 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21102100110, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (35135493120).

21102100110 is an abundant number, since it is smaller than the sum of its proper divisors (49168886130).

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

21102100110 is a wasteful number, since it uses less digits than its factorization.

21102100110 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 992 (or 989 counting only the distinct ones).

The product of its (nonzero) digits is 4, while the sum is 9.

Adding to 21102100110 its reverse (1100120112), we get a palindrome (22202220222).

The spelling of 21102100110 in words is "twenty-one billion, one hundred two million, one hundred thousand, one hundred ten".