21111000000 has 392 divisors, whose sum is σ = 72389073408. Its totient is φ = 5424000000.

The previous prime is 21110999977. The next prime is 21111000007. The reversal of 21111000000 is 11112.

It is a Harshad number since it is a multiple of its sum of digits (6).

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 not an unprimeable number, because it can be changed into a prime (21111000007) by changing a digit.

It is a polite number, since it can be written in 55 ways as a sum of consecutive naturals, for example, 92999887 + ... + 93000113.

Almost surely, 2^21111000000 is an apocalyptic number.

21111000000 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 21111000000, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (36194536704).

21111000000 is an abundant number, since it is smaller than the sum of its proper divisors (51278073408).

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

21111000000 is an frugal number, since it uses more digits than its factorization.

21111000000 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 303 (or 268 counting only the distinct ones).

The product of its (nonzero) digits is 2, while the sum is 6.

Adding to 21111000000 its reverse (11112), we get a palindrome (21111011112).

The spelling of 21111000000 in words is "twenty-one billion, one hundred eleven million", and thus it is an aban number.