21202121121220 has 192 divisors, whose sum is σ = 48844023814656. Its totient is φ = 7683938795520.

The previous prime is 21202121121193. The next prime is 21202121121221. The reversal of 21202121121220 is 2212112120212.

It is not an unprimeable number, because it can be changed into a prime (21202121121221) by changing a digit.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 2229216265 + ... + 2229225775.

It is an arithmetic number, because the mean of its divisors is an integer number (254395957368).

Almost surely, 2^{21202121121220} is an apocalyptic number.

21202121121220 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 21202121121220, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (24422011907328).

21202121121220 is an abundant number, since it is smaller than the sum of its proper divisors (27641902693436).

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

21202121121220 is a wasteful number, since it uses less digits than its factorization.

21202121121220 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10350 (or 10348 counting only the distinct ones).

The product of its (nonzero) digits is 128, while the sum is 19.

Adding to 21202121121220 its reverse (2212112120212), we get a palindrome (23414233241432).

The spelling of 21202121121220 in words is "twenty-one trillion, two hundred two billion, one hundred twenty-one million, one hundred twenty-one thousand, two hundred twenty".