21111021201220 has 48 divisors (see below), whose sum is σ = 45403658863920. Its totient is φ = 8242152062976.

The previous prime is 21111021201181. The next prime is 21111021201271. The reversal of 21111021201220 is 2210212011112.

It can be written as a sum of positive squares in 8 ways, for example, as 1327882866244 + 19783138334976 = 1152338^2 + 4447824^2 .

It is a junction number, because it is equal to n+sod(n) for n = 21111021201194 and 21111021201203.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 51391425 + ... + 51800584.

It is an arithmetic number, because the mean of its divisors is an integer number (945909559665).

Almost surely, 2^{21111021201220} is an apocalyptic number.

21111021201220 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21111021201220 is an abundant number, since it is smaller than the sum of its proper divisors (24292637662700).

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

21111021201220 is a wasteful number, since it uses less digits than its factorization.

21111021201220 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 103192264 (or 103192262 counting only the distinct ones).

The product of its (nonzero) digits is 32, while the sum is 16.

Adding to 21111021201220 its reverse (2210212011112), we get a palindrome (23321233212332).

The spelling of 21111021201220 in words is "twenty-one trillion, one hundred eleven billion, twenty-one million, two hundred one thousand, two hundred twenty".