21000021111000 has 1536 divisors, whose sum is σ = 78881493600000. Its totient is φ = 5018311065600.

The previous prime is 21000021110953. The next prime is 21000021111001. The reversal of 21000021111000 is 11112000012.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (9).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21000021111001) by changing a digit.

It is a polite number, since it can be written in 383 ways as a sum of consecutive naturals, for example, 71672426854 + ... + 71672427146.

Almost surely, 2^{21000021111000} is an apocalyptic number.

21000021111000 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 21000021111000, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (39440746800000).

21000021111000 is an abundant number, since it is smaller than the sum of its proper divisors (57881472489000).

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

21000021111000 is a wasteful number, since it uses less digits than its factorization.

21000021111000 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 614 (or 597 counting only the distinct ones).

The product of its (nonzero) digits is 4, while the sum is 9.

Adding to 21000021111000 its reverse (11112000012), we get a palindrome (21011133111012).

The spelling of 21000021111000 in words is "twenty-one trillion, twenty-one million, one hundred eleven thousand".