21111100220 has 36 divisors (see below), whose sum is σ = 51571404360. Its totient is φ = 7238091168.

The previous prime is 21111100181. The next prime is 21111100289. The reversal of 21111100220 is 2200111112.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 10769990 + ... + 10771949.

It is an arithmetic number, because the mean of its divisors is an integer number (1432539010).

Almost surely, 2^21111100220 is an apocalyptic number.

21111100220 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21111100220 is an abundant number, since it is smaller than the sum of its proper divisors (30460304140).

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

21111100220 is a wasteful number, since it uses less digits than its factorization.

21111100220 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 21541962 (or 21541953 counting only the distinct ones).

The product of its (nonzero) digits is 8, while the sum is 11.

Adding to 21111100220 its reverse (2200111112), we get a palindrome (23311211332).

The spelling of 21111100220 in words is "twenty-one billion, one hundred eleven million, one hundred thousand, two hundred twenty".