221311212 has 12 divisors (see below), whose sum is σ = 516392856. Its totient is φ = 73770400.

The previous prime is 221311193. The next prime is 221311217. The reversal of 221311212 is 212113122.

221311212 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 nude number because it is divisible by every one of its digits.

It is a junction number, because it is equal to n+sod(n) for n = 221311191 and 221311200.

It is not an unprimeable number, because it can be changed into a prime (221311217) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 9221289 + ... + 9221312.

It is an arithmetic number, because the mean of its divisors is an integer number (43032738).

Almost surely, 2^221311212 is an apocalyptic number.

It is an amenable number.

221311212 is an abundant number, since it is smaller than the sum of its proper divisors (295081644).

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

221311212 is a wasteful number, since it uses less digits than its factorization.

221311212 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 18442608 (or 18442606 counting only the distinct ones).

The product of its digits is 48, while the sum is 15.

The square root of 221311212 is about 14876.5322572164. The cubic root of 221311212 is about 604.8780229014.

Adding to 221311212 its reverse (212113122), we get a palindrome (433424334).

The spelling of 221311212 in words is "two hundred twenty-one million, three hundred eleven thousand, two hundred twelve".