21110000000 has 128 divisors (see below), whose sum is σ = 52593615360. Its totient is φ = 8440000000.

The previous prime is 21109999993. The next prime is 21110000003. The reversal of 21110000000 is 1112.

It is a happy number.

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 (5).

It is a nialpdrome in base 10.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21110000003) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 9998945 + ... + 10001055.

It is an arithmetic number, because the mean of its divisors is an integer number (410887620).

Almost surely, 2^21110000000 is an apocalyptic number.

21110000000 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 21110000000, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (26296807680).

21110000000 is an abundant number, since it is smaller than the sum of its proper divisors (31483615360).

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

21110000000 is an frugal number, since it uses more digits than its factorization.

21110000000 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2160 (or 2118 counting only the distinct ones).

The product of its (nonzero) digits is 2, while the sum is 5.

Adding to 21110000000 its reverse (1112), we get a palindrome (21110001112).

The spelling of 21110000000 in words is "twenty-one billion, one hundred ten million", and thus it is an aban number.