21001022120020 has 48 divisors (see below), whose sum is σ = 44305173158400. Its totient is φ = 8361825903360.

The previous prime is 21001022120011. The next prime is 21001022120047. The reversal of 21001022120020 is 2002122010012.

It is a happy number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1009336 + ... + 6559024.

It is an arithmetic number, because the mean of its divisors is an integer number (923024440800).

Almost surely, 2^{21001022120020} is an apocalyptic number.

21001022120020 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21001022120020 is an abundant number, since it is smaller than the sum of its proper divisors (23304151038380).

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

21001022120020 is a wasteful number, since it uses less digits than its factorization.

21001022120020 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5550568 (or 5550566 counting only the distinct ones).

The product of its (nonzero) digits is 32, while the sum is 13.

Adding to 21001022120020 its reverse (2002122010012), we get a palindrome (23003144130032).

The spelling of 21001022120020 in words is "twenty-one trillion, one billion, twenty-two million, one hundred twenty thousand, twenty".