21211202221020 has 576 divisors, whose sum is σ = 77536394732160. Its totient is φ = 4799742345216.

The previous prime is 21211202220991. The next prime is 21211202221037. The reversal of 21211202221020 is 2012220211212.

It is a happy number.

21211202221020 is a `hidden beast` number, since 21 + 211 + 202 + 2 + 210 + 20 = 666.

It is a super-2 number, since 2×21211202221020² (a number of 27 digits) contains 22 as substring.

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

It is a junction number, because it is equal to n+sod(n) for n = 21211202220984 and 21211202221002.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 191 ways as a sum of consecutive naturals, for example, 1150709724 + ... + 1150728156.

It is an arithmetic number, because the mean of its divisors is an integer number (134611796410).

Almost surely, 2^{21211202221020} is an apocalyptic number.

21211202221020 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 21211202221020, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (38768197366080).

21211202221020 is an abundant number, since it is smaller than the sum of its proper divisors (56325192511140).

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

21211202221020 is a wasteful number, since it uses less digits than its factorization.

21211202221020 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 18899 (or 18884 counting only the distinct ones).

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

Adding to 21211202221020 its reverse (2012220211212), we get a palindrome (23223422432232).

The spelling of 21211202221020 in words is "twenty-one trillion, two hundred eleven billion, two hundred two million, two hundred twenty-one thousand, twenty".