21111200000000 has 432 divisors, whose sum is σ = 57585908016000. Its totient is φ = 7673600000000.

The previous prime is 21111199999999. The next prime is 21111200000071. The reversal of 21111200000000 is 211112.

It is a Harshad number since it is a multiple of its sum of digits (8).

It is an unprimeable number.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 8799998801 + ... + 8800001199.

It is an arithmetic number, because the mean of its divisors is an integer number (133300713000).

Almost surely, 2^{21111200000000} is an apocalyptic number.

21111200000000 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 21111200000000, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (28792954008000).

21111200000000 is an abundant number, since it is smaller than the sum of its proper divisors (36474708016000).

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

21111200000000 is an frugal number, since it uses more digits than its factorization.

21111200000000 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2472 (or 2417 counting only the distinct ones).

The product of its (nonzero) digits is 4, while the sum is 8.

Adding to 21111200000000 its reverse (211112), we get a palindrome (21111200211112).

21111200000000 divided by its reverse (211112) gives a 8-th power (100000000 = 10⁸).

It can be divided in two parts, 211 and 11200000000, that added together give a palindrome (11200000211).

The spelling of 21111200000000 in words is "twenty-one trillion, one hundred eleven billion, two hundred million", and thus it is an aban number.