21020121222210 has 672 divisors, whose sum is σ = 65478219210432. Its totient is φ = 4815467470080.

The previous prime is 21020121222187. The next prime is 21020121222211. The reversal of 21020121222210 is 1222212102012.

It is a happy number.

21020121222210 is a `hidden beast` number, since 2 + 10 + 201 + 21 + 222 + 210 = 666.

It is a Harshad number since it is a multiple of its sum of digits (18).

It is not an unprimeable number, because it can be changed into a prime (21020121222211) by changing a digit.

It is a polite number, since it can be written in 335 ways as a sum of consecutive naturals, for example, 16992821712 + ... + 16992822948.

It is an arithmetic number, because the mean of its divisors is an integer number (97437826206).

Almost surely, 2^{21020121222210} is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21020121222210, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (32739109605216).

21020121222210 is an abundant number, since it is smaller than the sum of its proper divisors (44458097988222).

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

21020121222210 is a wasteful number, since it uses less digits than its factorization.

21020121222210 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1898 (or 1864 counting only the distinct ones).

The product of its (nonzero) digits is 128, while the sum is 18.

Adding to 21020121222210 its reverse (1222212102012), we get a palindrome (22242333324222).

The spelling of 21020121222210 in words is "twenty-one trillion, twenty billion, one hundred twenty-one million, two hundred twenty-two thousand, two hundred ten".