21202121111020 has 24 divisors (see below), whose sum is σ = 44524791171504. Its totient is φ = 8480784284736.

The previous prime is 21202121111009. The next prime is 21202121111021. The reversal of 21202121111020 is 2011112120212.

It is a junction number, because it is equal to n+sod(n) for n = 21202121110985 and 21202121111003.

It is not an unprimeable number, because it can be changed into a prime (21202121111021) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1254022 + ... + 6631501.

It is an arithmetic number, because the mean of its divisors is an integer number (1855199632146).

Almost surely, 2^{21202121111020} is an apocalyptic number.

21202121111020 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21202121111020 is an abundant number, since it is smaller than the sum of its proper divisors (23322670060484).

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

21202121111020 is a wasteful number, since it uses less digits than its factorization.

21202121111020 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8019969 (or 8019967 counting only the distinct ones).

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

Adding to 21202121111020 its reverse (2011112120212), we get a palindrome (23213233231232).

The spelling of 21202121111020 in words is "twenty-one trillion, two hundred two billion, one hundred twenty-one million, one hundred eleven thousand, twenty".