212121221210220 has 384 divisors, whose sum is σ = 700663474667520. Its totient is φ = 46951678033920.

The previous prime is 212121221210113. The next prime is 212121221210233. The reversal of 212121221210220 is 22012122121212.

It is a Harshad number since it is a multiple of its sum of digits (21).

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 127 ways as a sum of consecutive naturals, for example, 531082309 + ... + 531481571.

It is an arithmetic number, because the mean of its divisors is an integer number (1824644465280).

Almost surely, 2^{212121221210220} is an apocalyptic number.

212121221210220 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 212121221210220, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (350331737333760).

212121221210220 is an abundant number, since it is smaller than the sum of its proper divisors (488542253457300).

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

212121221210220 is a wasteful number, since it uses less digits than its factorization.

212121221210220 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 399665 (or 399663 counting only the distinct ones).

The product of its (nonzero) digits is 256, while the sum is 21.

Adding to 212121221210220 its reverse (22012122121212), we get a palindrome (234133343331432).

The spelling of 212121221210220 in words is "two hundred twelve trillion, one hundred twenty-one billion, two hundred twenty-one million, two hundred ten thousand, two hundred twenty".