21012220120200 has 192 divisors, whose sum is σ = 66534110026560. Its totient is φ = 5483685841920.

The previous prime is 21012220120193. The next prime is 21012220120201. The reversal of 21012220120200 is 202102221012.

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 21012220120200.

It is not an unprimeable number, because it can be changed into a prime (21012220120201) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 11792407 + ... + 13456793.

It is an arithmetic number, because the mean of its divisors is an integer number (346531823055).

Almost surely, 2^{21012220120200} is an apocalyptic number.

21012220120200 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 21012220120200, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (33267055013280).

21012220120200 is an abundant number, since it is smaller than the sum of its proper divisors (45521889906360).

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

21012220120200 is a wasteful number, since it uses less digits than its factorization.

21012220120200 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1664856 (or 1664847 counting only the distinct ones).

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

Adding to 21012220120200 its reverse (202102221012), we get a palindrome (21214322341212).

The spelling of 21012220120200 in words is "twenty-one trillion, twelve billion, two hundred twenty million, one hundred twenty thousand, two hundred".