21111111000 has 768 divisors, whose sum is σ = 86622307200. Its totient is φ = 4800902400.

The previous prime is 21111110981. The next prime is 21111111023. The reversal of 21111111000 is 11111112.

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

It is a super Niven number, because it is divisible the sum of any subset of its (nonzero) digits.

It is a nialpdrome in base 10.

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, 107162902 + ... + 107163098.

Almost surely, 2^21111111000 is an apocalyptic number.

21111111000 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 21111111000, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (43311153600).

21111111000 is an abundant number, since it is smaller than the sum of its proper divisors (65511196200).

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

21111111000 is an equidigital number, since it uses as much as digits as its factorization.

21111111000 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 253 (or 214 counting only the distinct ones).

The product of its (nonzero) digits is 2, while the sum is 9.

Adding to 21111111000 its reverse (11111112), we get a palindrome (21122222112).

It can be divided in two parts, 211111 and 11000, that added together give a triangular number (222111 = T₆₆₆).

The spelling of 21111111000 in words is "twenty-one billion, one hundred eleven million, one hundred eleven thousand".