21012221200020 has 48 divisors (see below), whose sum is σ = 58844454144000. Its totient is φ = 5602284245376.

The previous prime is 21012221199979. The next prime is 21012221200021. The reversal of 21012221200020 is 2000212221012.

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

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21012221200021) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 30112852 + ... + 30802731.

It is an arithmetic number, because the mean of its divisors is an integer number (1225926128000).

Almost surely, 2^{21012221200020} is an apocalyptic number.

21012221200020 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21012221200020 is an abundant number, since it is smaller than the sum of its proper divisors (37832232943980).

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

21012221200020 is a wasteful number, since it uses less digits than its factorization.

21012221200020 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 60921344 (or 60921342 counting only the distinct ones).

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

Adding to 21012221200020 its reverse (2000212221012), we get a palindrome (23012433421032).

The spelling of 21012221200020 in words is "twenty-one trillion, twelve billion, two hundred twenty-one million, two hundred thousand, twenty".