21212210212 has 6 divisors (see below), whose sum is σ = 37121367878. Its totient is φ = 10606105104.

The previous prime is 21212210209. The next prime is 21212210213. The reversal of 21212210212 is 21201221212.

It is a happy number.

It can be written as a sum of positive squares in only one way, i.e., 12491638756 + 8720571456 = 111766^2 + 93384^2 .

It is not an unprimeable number, because it can be changed into a prime (21212210213) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 2651526273 + ... + 2651526280.

Almost surely, 2^21212210212 is an apocalyptic number.

It is an amenable number.

21212210212 is a deficient number, since it is larger than the sum of its proper divisors (15909157666).

21212210212 is a wasteful number, since it uses less digits than its factorization.

21212210212 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5303052557 (or 5303052555 counting only the distinct ones).

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

Adding to 21212210212 its reverse (21201221212), we get a palindrome (42413431424).

The spelling of 21212210212 in words is "twenty-one billion, two hundred twelve million, two hundred ten thousand, two hundred twelve".