212121122221020 has 192 divisors, whose sum is σ = 626754123072000. Its totient is φ = 53455276339200.

The previous prime is 212121122220899. The next prime is 212121122221049. The reversal of 212121122221020 is 20122221121212.

It is a congruent number.

It is an unprimeable number.

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, 1796800995 + ... + 1796919045.

It is an arithmetic number, because the mean of its divisors is an integer number (3264344391000).

Almost surely, 2^{212121122221020} is an apocalyptic number.

212121122221020 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 212121122221020, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (313377061536000).

212121122221020 is an abundant number, since it is smaller than the sum of its proper divisors (414633000850980).

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

212121122221020 is a wasteful number, since it uses less digits than its factorization.

212121122221020 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 121988 (or 121986 counting only the distinct ones).

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

Adding to 212121122221020 its reverse (20122221121212), we get a palindrome (232243343342232).

The spelling of 212121122221020 in words is "two hundred twelve trillion, one hundred twenty-one billion, one hundred twenty-two million, two hundred twenty-one thousand, twenty".