221021210212 has 18 divisors (see below), whose sum is σ = 425146171814. Its totient is φ = 100464186240.

The previous prime is 221021210197. The next prime is 221021210219. The reversal of 221021210212 is 212012120122.

It is a happy number.

It can be written as a sum of positive squares in only one way, i.e., 121868017216 + 99153192996 = 349096^2 + 314886^2 .

It is not an unprimeable number, because it can be changed into a prime (221021210219) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 228327213 + ... + 228328180.

Almost surely, 2^221021210212 is an apocalyptic number.

221021210212 is a gapful number since it is divisible by the number (22) formed by its first and last digit.

It is an amenable number.

221021210212 is a deficient number, since it is larger than the sum of its proper divisors (204124961602).

221021210212 is a wasteful number, since it uses less digits than its factorization.

221021210212 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 456655419 (or 456655406 counting only the distinct ones).

The product of its (nonzero) digits is 64, while the sum is 16.

Adding to 221021210212 its reverse (212012120122), we get a palindrome (433033330334).

The spelling of 221021210212 in words is "two hundred twenty-one billion, twenty-one million, two hundred ten thousand, two hundred twelve".