221212261212 has 12 divisors (see below), whose sum is σ = 516161942856. Its totient is φ = 73737420400.

The previous prime is 221212261211. The next prime is 221212261241. The reversal of 221212261212 is 212162212122.

It is a happy number.

221212261212 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a tau number, because it is divible by the number of its divisors (12).

It is a super-2 number, since 2×221212261212² (a number of 23 digits) contains 22 as substring.

It is a nude number because it is divisible by every one of its digits.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (221212261211) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 9217177539 + ... + 9217177562.

It is an arithmetic number, because the mean of its divisors is an integer number (43013495238).

Almost surely, 2^221212261212 is an apocalyptic number.

It is an amenable number.

221212261212 is an abundant number, since it is smaller than the sum of its proper divisors (294949681644).

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

221212261212 is a wasteful number, since it uses less digits than its factorization.

221212261212 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 18434355108 (or 18434355106 counting only the distinct ones).

The product of its digits is 768, while the sum is 24.

Adding to 221212261212 its reverse (212162212122), we get a palindrome (433374473334).

The spelling of 221212261212 in words is "two hundred twenty-one billion, two hundred twelve million, two hundred sixty-one thousand, two hundred twelve".