221021012220 has 96 divisors (see below), whose sum is σ = 637874189568. Its totient is φ = 57147965952.

The previous prime is 221021012203. The next prime is 221021012249. The reversal of 221021012220 is 22210120122.

221021012220 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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 221021012220.

It is a congruent number.

It is an unprimeable number.

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 31 ways as a sum of consecutive naturals, for example, 40807 + ... + 666113.

It is an arithmetic number, because the mean of its divisors is an integer number (6644522808).

Almost surely, 2^221021012220 is an apocalyptic number.

221021012220 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 221021012220, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (318937094784).

221021012220 is an abundant number, since it is smaller than the sum of its proper divisors (416853177348).

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

221021012220 is a wasteful number, since it uses less digits than its factorization.

221021012220 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 625499 (or 625497 counting only the distinct ones).

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

Adding to 221021012220 its reverse (22210120122), we get a palindrome (243231132342).

The spelling of 221021012220 in words is "two hundred twenty-one billion, twenty-one million, twelve thousand, two hundred twenty".