21210002012220 has 384 divisors, whose sum is σ = 73187422371840. Its totient is φ = 4481965716480.

The previous prime is 21210002012149. The next prime is 21210002012233. The reversal of 21210002012220 is 2221020001212.

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 21210002012220.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 127 ways as a sum of consecutive naturals, for example, 61649517 + ... + 61992603.

It is an arithmetic number, because the mean of its divisors is an integer number (190592245760).

Almost surely, 2^{21210002012220} is an apocalyptic number.

21210002012220 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 21210002012220, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (36593711185920).

21210002012220 is an abundant number, since it is smaller than the sum of its proper divisors (51977420359620).

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

21210002012220 is a wasteful number, since it uses less digits than its factorization.

21210002012220 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 343313 (or 343311 counting only the distinct ones).

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

Adding to 21210002012220 its reverse (2221020001212), we get a palindrome (23431022013432).

The spelling of 21210002012220 in words is "twenty-one trillion, two hundred ten billion, two million, twelve thousand, two hundred twenty".