21100000000000 has 288 divisors, whose sum is σ = 52987060329840. Its totient is φ = 8400000000000.

The previous prime is 21099999999997. The next prime is 21100000000039. The reversal of 21100000000000 is 112.

It is a Harshad number since it is a multiple of its sum of digits (4).

It is a nialpdrome in base 10.

It is a junction number, because it is equal to n+sod(n) for n = 21099999999899 and 21099999999908.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 99999999895 + ... + 100000000105.

Almost surely, 2^{21100000000000} is an apocalyptic number.

21100000000000 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 21100000000000, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (26493530164920).

21100000000000 is an abundant number, since it is smaller than the sum of its proper divisors (31887060329840).

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

21100000000000 is an frugal number, since it uses more digits than its factorization.

21100000000000 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 288 (or 218 counting only the distinct ones).

The product of its (nonzero) digits is 2, while the sum is 4.

Adding to 21100000000000 its reverse (112), we get a palindrome (21100000000112).

The spelling of 21100000000000 in words is "twenty-one trillion, one hundred billion", and thus it is an aban number.