221221212444 has 18 divisors (see below), whose sum is σ = 559198064880. Its totient is φ = 73740404136.

The previous prime is 221221212403. The next prime is 221221212463. The reversal of 221221212444 is 444212122122.

221221212444 is a `hidden beast` number, since 2 + 2 + 1 + 2 + 2 + 1 + 212 + 444 = 666.

221221212444 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 (18).

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

It is a congruent number.

It is an unprimeable number.

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 5 ways as a sum of consecutive naturals, for example, 3072516804 + ... + 3072516875.

It is an arithmetic number, because the mean of its divisors is an integer number (31066559160).

Almost surely, 2^221221212444 is an apocalyptic number.

It is an amenable number.

221221212444 is an abundant number, since it is smaller than the sum of its proper divisors (337976852436).

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

221221212444 is a wasteful number, since it uses less digits than its factorization.

221221212444 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6145033689 (or 6145033684 counting only the distinct ones).

The product of its digits is 4096, while the sum is 27.

Adding to 221221212444 its reverse (444212122122), we get a palindrome (665433334566).

The spelling of 221221212444 in words is "two hundred twenty-one billion, two hundred twenty-one million, two hundred twelve thousand, four hundred forty-four".