221212021212 has 576 divisors, whose sum is σ = 772757766144. Its totient is φ = 51687383040.

The previous prime is 221212021157. The next prime is 221212021231. The reversal of 221212021212 is 212120212122.

It is a happy number.

221212021212 is a `hidden beast` number, since 221 + 212 + 0 + 21 + 212 = 666.

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

It is a congruent number.

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 191 ways as a sum of consecutive naturals, for example, 63876993 + ... + 63880455.

It is an arithmetic number, because the mean of its divisors is an integer number (1341593344).

Almost surely, 2^221212021212 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 221212021212, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (386378883072).

221212021212 is an abundant number, since it is smaller than the sum of its proper divisors (551545744932).

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

221212021212 is a wasteful number, since it uses less digits than its factorization.

221212021212 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3578 (or 3573 counting only the distinct ones).

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

Adding to 221212021212 its reverse (212120212122), we get a palindrome (433332233334).

It can be divided in two parts, 2 and 21212021212, that multiplied together give a palindrome (42424042424).

The spelling of 221212021212 in words is "two hundred twenty-one billion, two hundred twelve million, twenty-one thousand, two hundred twelve".