21000212122200 has 384 divisors, whose sum is σ = 68154100358400. Its totient is φ = 5343351736320.

The previous prime is 21000212122189. The next prime is 21000212122249. The reversal of 21000212122200 is 222121200012.

It is a Harshad number since it is a multiple of its sum of digits (15).

It is a self number, because there is not a number n which added to its sum of digits gives 21000212122200.

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, 4446369039 + ... + 4446373761.

It is an arithmetic number, because the mean of its divisors is an integer number (177484636350).

Almost surely, 2^{21000212122200} is an apocalyptic number.

21000212122200 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 21000212122200, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (34077050179200).

21000212122200 is an abundant number, since it is smaller than the sum of its proper divisors (47153888236200).

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

21000212122200 is a wasteful number, since it uses less digits than its factorization.

21000212122200 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8611 (or 8602 counting only the distinct ones).

The product of its (nonzero) digits is 64, while the sum is 15.

Adding to 21000212122200 its reverse (222121200012), we get a palindrome (21222333322212).

The spelling of 21000212122200 in words is "twenty-one trillion, two hundred twelve million, one hundred twenty-two thousand, two hundred".