21000001200000 has 768 divisors, whose sum is σ = 72525008102400. Its totient is φ = 5378780160000.

The previous prime is 21000001199999. The next prime is 21000001200047. The reversal of 21000001200000 is 210000012.

It is a happy number.

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 congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 3507597007 + ... + 3507602993.

It is an arithmetic number, because the mean of its divisors is an integer number (94433604300).

Almost surely, 2^{21000001200000} is an apocalyptic number.

21000001200000 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 21000001200000, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (36262504051200).

21000001200000 is an abundant number, since it is smaller than the sum of its proper divisors (51525006902400).

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

21000001200000 is an frugal number, since it uses more digits than its factorization.

21000001200000 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6145 (or 6113 counting only the distinct ones).

The product of its (nonzero) digits is 4, while the sum is 6.

Adding to 21000001200000 its reverse (210000012), we get a palindrome (21000211200012).

21000001200000 divided by its reverse (210000012) gives a 5-th power (100000 = 10⁵).

The spelling of 21000001200000 in words is "twenty-one trillion, one million, two hundred thousand".