221221210212 has 60 divisors (see below), whose sum is σ = 584041928316. Its totient is φ = 73010289600.

The previous prime is 221221210207. The next prime is 221221210213. The reversal of 221221210212 is 212012122122.

It is a happy number.

221221210212 is a `hidden beast` number, since 2 + 21 + 221 + 210 + 212 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 216956597796 + 4264612416 = 465786^2 + 65304^2 .

It is a Harshad number since it is a multiple of its sum of digits (18).

It is not an unprimeable number, because it can be changed into a prime (221221210213) by changing a digit.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 3347383 + ... + 3412830.

Almost surely, 2^221221210212 is an apocalyptic number.

It is an amenable number.

221221210212 is an abundant number, since it is smaller than the sum of its proper divisors (362820718104).

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

221221210212 is a wasteful number, since it uses less digits than its factorization.

221221210212 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6760330 (or 6760319 counting only the distinct ones).

The product of its (nonzero) digits is 128, while the sum is 18.

Adding to 221221210212 its reverse (212012122122), we get a palindrome (433233332334).

The spelling of 221221210212 in words is "two hundred twenty-one billion, two hundred twenty-one million, two hundred ten thousand, two hundred twelve".