21043000000000 has 400 divisors, whose sum is σ = 57363919907184. Its totient is φ = 7648000000000.

The previous prime is 21042999999943. The next prime is 21043000000013. The reversal of 21043000000000 is 34012.

It is a tau number, because it is divible by the number of its divisors (400).

It is a Harshad number since it is a multiple of its sum of digits (10).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 39 ways as a sum of consecutive naturals, for example, 10999999044 + ... + 11000000956.

Almost surely, 2^{21043000000000} is an apocalyptic number.

21043000000000 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 21043000000000, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (28681959953592).

21043000000000 is an abundant number, since it is smaller than the sum of its proper divisors (36320919907184).

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

21043000000000 is an frugal number, since it uses more digits than its factorization.

21043000000000 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1987 (or 1931 counting only the distinct ones).

The product of its (nonzero) digits is 24, while the sum is 10.

Adding to 21043000000000 its reverse (34012), we get a palindrome (21043000034012).

The spelling of 21043000000000 in words is "twenty-one trillion, forty-three billion", and thus it is an aban number and an uban number.