21111011220 has 48 divisors (see below), whose sum is σ = 63657820800. Its totient is φ = 5196556416.

The previous prime is 21111011189. The next prime is 21111011231. The reversal of 21111011220 is 2211011112.

It is a Harshad number since it is a multiple of its sum of digits (12).

It is a junction number, because it is equal to n+sod(n) for n = 21111011196 and 21111011205.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 13531920 + ... + 13533479.

It is an arithmetic number, because the mean of its divisors is an integer number (1326204600).

Almost surely, 2^21111011220 is an apocalyptic number.

21111011220 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21111011220 is an abundant number, since it is smaller than the sum of its proper divisors (42546809580).

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

21111011220 is a wasteful number, since it uses less digits than its factorization.

21111011220 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 27065424 (or 27065422 counting only the distinct ones).

The product of its (nonzero) digits is 8, while the sum is 12.

Adding to 21111011220 its reverse (2211011112), we get a palindrome (23322022332).

The spelling of 21111011220 in words is "twenty-one billion, one hundred eleven million, eleven thousand, two hundred twenty".