221220312 has 32 divisors (see below), whose sum is σ = 555379200. Its totient is φ = 73429664.

The previous prime is 221220301. The next prime is 221220313. The reversal of 221220312 is 213022122.

It is a happy number.

221220312 is digitally balanced in base 3, because in such base it contains all the possibile digits an equal number of times.

It is a junction number, because it is equal to n+sod(n) for n = 221220291 and 221220300.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (221220313) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 13548 + ... + 25019.

It is an arithmetic number, because the mean of its divisors is an integer number (17355600).

Almost surely, 2^221220312 is an apocalyptic number.

It is an amenable number.

221220312 is an abundant number, since it is smaller than the sum of its proper divisors (334158888).

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

221220312 is a wasteful number, since it uses less digits than its factorization.

221220312 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 38815 (or 38811 counting only the distinct ones).

The product of its (nonzero) digits is 96, while the sum is 15.

The square root of 221220312 is about 14873.4767959613. The cubic root of 221220312 is about 604.7951969398.

Adding to 221220312 its reverse (213022122), we get a palindrome (434242434).

The spelling of 221220312 in words is "two hundred twenty-one million, two hundred twenty thousand, three hundred twelve".