21001100120000 has 840 divisors, whose sum is σ = 71169616370160. Its totient is φ = 6042193920000.

The previous prime is 21001100119999. The next prime is 21001100120023. The reversal of 21001100120000 is 2100110012.

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

It is a self number, because there is not a number n which added to its sum of digits gives 21001100120000.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 119 ways as a sum of consecutive naturals, for example, 280242536 + ... + 280317464.

It is an arithmetic number, because the mean of its divisors is an integer number (84725733774).

Almost surely, 2^{21001100120000} is an apocalyptic number.

21001100120000 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 21001100120000, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (35584808185080).

21001100120000 is an abundant number, since it is smaller than the sum of its proper divisors (50168516250160).

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

21001100120000 is a wasteful number, since it uses less digits than its factorization.

21001100120000 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 74999 (or 74967 counting only the distinct ones).

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

Adding to 21001100120000 its reverse (2100110012), we get a palindrome (21003200230012).

21001100120000 divided by its reverse (2100110012) gives a 4-th power (10000 = 10⁴).

It can be divided in two parts, 21001 and 100120000, that added together give a palindrome (100141001).

The spelling of 21001100120000 in words is "twenty-one trillion, one billion, one hundred million, one hundred twenty thousand".