21101202220 has 96 divisors (see below), whose sum is σ = 51776524800. Its totient is φ = 7220687040.

The previous prime is 21101202217. The next prime is 21101202251. The reversal of 21101202220 is 2220210112.

It is a happy number.

It is a self number, because there is not a number n which added to its sum of digits gives 21101202220.

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, 3914367 + ... + 3919753.

It is an arithmetic number, because the mean of its divisors is an integer number (539338800).

Almost surely, 2^21101202220 is an apocalyptic number.

21101202220 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 21101202220, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (25888262400).

21101202220 is an abundant number, since it is smaller than the sum of its proper divisors (30675322580).

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

21101202220 is a wasteful number, since it uses less digits than its factorization.

21101202220 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5988 (or 5972 counting only the distinct ones).

The product of its (nonzero) digits is 32, while the sum is 13.

Adding to 21101202220 its reverse (2220210112), we get a palindrome (23321412332).

The spelling of 21101202220 in words is "twenty-one billion, one hundred one million, two hundred two thousand, two hundred twenty".