21101220220 has 24 divisors (see below), whose sum is σ = 44326900800. Its totient is φ = 8437756992.

The previous prime is 21101220209. The next prime is 21101220253. The reversal of 21101220220 is 2202210112.

It is a happy number.

It is a super-2 number, since 2×21101220220² (a number of 21 digits) contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 21101220220.

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 7 ways as a sum of consecutive naturals, for example, 106755 + ... + 231514.

It is an arithmetic number, because the mean of its divisors is an integer number (1846954200).

Almost surely, 2^21101220220 is an apocalyptic number.

21101220220 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21101220220 is an abundant number, since it is smaller than the sum of its proper divisors (23225680580).

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

21101220220 is a wasteful number, since it uses less digits than its factorization.

21101220220 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 341397 (or 341395 counting only the distinct ones).

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

Adding to 21101220220 its reverse (2202210112), we get a palindrome (23303430332).

The spelling of 21101220220 in words is "twenty-one billion, one hundred one million, two hundred twenty thousand, two hundred twenty".