21111001221020 has 12 divisors (see below), whose sum is σ = 44333102564184. Its totient is φ = 8444400488400.

The previous prime is 21111001221019. The next prime is 21111001221031. The reversal of 21111001221020 is 2012210011112.

It is a junction number, because it is equal to n+sod(n) for n = 21111001220986 and 21111001221004.

It is a congruent number.

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 3 ways as a sum of consecutive naturals, for example, 527775030506 + ... + 527775030545.

It is an arithmetic number, because the mean of its divisors is an integer number (3694425213682).

Almost surely, 2^{21111001221020} is an apocalyptic number.

21111001221020 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21111001221020 is an abundant number, since it is smaller than the sum of its proper divisors (23222101343164).

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

21111001221020 is a wasteful number, since it uses less digits than its factorization.

21111001221020 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1055550061060 (or 1055550061058 counting only the distinct ones).

The product of its (nonzero) digits is 16, while the sum is 14.

Adding to 21111001221020 its reverse (2012210011112), we get a palindrome (23123211232132).

The spelling of 21111001221020 in words is "twenty-one trillion, one hundred eleven billion, one million, two hundred twenty-one thousand, twenty".