221221443212 has 96 divisors (see below), whose sum is σ = 500171051520. Its totient is φ = 83074360320.

The previous prime is 221221443203. The next prime is 221221443221. The reversal of 221221443212 is 212344122122.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (221221443203) and next prime (221221443221).

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 5221988 + ... + 5264180.

It is an arithmetic number, because the mean of its divisors is an integer number (5210115120).

Almost surely, 2^221221443212 is an apocalyptic number.

221221443212 is a gapful number since it is divisible by the number (22) 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 221221443212, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (250085525760).

221221443212 is an abundant number, since it is smaller than the sum of its proper divisors (278949608308).

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

221221443212 is a wasteful number, since it uses less digits than its factorization.

221221443212 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 42831 (or 42829 counting only the distinct ones).

The product of its digits is 3072, while the sum is 26.

Adding to 221221443212 its reverse (212344122122), we get a palindrome (433565565334).

The spelling of 221221443212 in words is "two hundred twenty-one billion, two hundred twenty-one million, four hundred forty-three thousand, two hundred twelve".