21001020202120 has 64 divisors (see below), whose sum is σ = 54009238320000. Its totient is φ = 7199467791360.

The previous prime is 21001020202111. The next prime is 21001020202139. The reversal of 21001020202120 is 2120202010012.

It is a happy number.

It is a self number, because there is not a number n which added to its sum of digits gives 21001020202120.

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, 2301745 + ... + 6877504.

It is an arithmetic number, because the mean of its divisors is an integer number (843894348750).

Almost surely, 2^{21001020202120} is an apocalyptic number.

21001020202120 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21001020202120 is an abundant number, since it is smaller than the sum of its proper divisors (33008218117880).

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

21001020202120 is a wasteful number, since it uses less digits than its factorization.

21001020202120 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9187438 (or 9187434 counting only the distinct ones).

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

Adding to 21001020202120 its reverse (2120202010012), we get a palindrome (23121222212132).

The spelling of 21001020202120 in words is "twenty-one trillion, one billion, twenty million, two hundred two thousand, one hundred twenty".