21021001220120 has 128 divisors (see below), whose sum is σ = 52347285504000. Its totient is φ = 7532944473600.

The previous prime is 21021001220083. The next prime is 21021001220209. The reversal of 21021001220120 is 2102210012012.

It is a junction number, because it is equal to n+sod(n) for n = 21021001220095 and 21021001220104.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 69733481 + ... + 70034279.

It is an arithmetic number, because the mean of its divisors is an integer number (408963168000).

Almost surely, 2^{21021001220120} is an apocalyptic number.

21021001220120 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21021001220120, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (26173642752000).

21021001220120 is an abundant number, since it is smaller than the sum of its proper divisors (31326284283880).

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

21021001220120 is a wasteful number, since it uses less digits than its factorization.

21021001220120 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 303129 (or 303125 counting only the distinct ones).

The product of its (nonzero) digits is 32, while the sum is 14.

Adding to 21021001220120 its reverse (2102210012012), we get a palindrome (23123211232132).

The spelling of 21021001220120 in words is "twenty-one trillion, twenty-one billion, one million, two hundred twenty thousand, one hundred twenty".