21201021222210 has 128 divisors (see below), whose sum is σ = 57275955878400. Its totient is φ = 5579968953600.

The previous prime is 21201021222169. The next prime is 21201021222217. The reversal of 21201021222210 is 1222212010212.

It is a happy number.

21201021222210 is a `hidden beast` number, since 21 + 201 + 0 + 212 + 22 + 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 (21201021222217) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 7418331 + ... + 9870849.

It is an arithmetic number, because the mean of its divisors is an integer number (447468405300).

Almost surely, 2^{21201021222210} is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21201021222210, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (28637977939200).

21201021222210 is an abundant number, since it is smaller than the sum of its proper divisors (36074934656190).

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

21201021222210 is a wasteful number, since it uses less digits than its factorization.

21201021222210 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2452953 (or 2452947 counting only the distinct ones).

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

Adding to 21201021222210 its reverse (1222212010212), we get a palindrome (22423233232422).

The spelling of 21201021222210 in words is "twenty-one trillion, two hundred one billion, twenty-one million, two hundred twenty-two thousand, two hundred ten".