21210212 has 12 divisors (see below), whose sum is σ = 37346736.
Its totient is φ = 10539720.
The previous prime is 21210197. The next prime is 21210221. The reversal of 21210212 is 21201212.
Adding to 21210212 its reverse (21201212), we get a palindrome (42411424).
It is a happy number.
It is a junction number, because it is equal to n+sod(n) for n = 21210193 and 21210202.
It is an unprimeable number.
It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 15614 + ... + 16917.
It is an arithmetic number, because the mean of its divisors is an integer number (3112228).
Almost surely, 221210212 is an apocalyptic number.
It is an amenable number.
21210212 is a deficient number, since it is larger than the sum of its proper divisors (16136524).
21210212 is a wasteful number, since it uses less digits than its factorization.
21210212 is an evil number, because the sum of its binary digits is even.
The sum of its prime factors is 32698 (or 32696 counting only the distinct ones).
The product of its (nonzero) digits is 16, while the sum is 11.
The square root of 21210212 is about 4605.4545921114.
The cubic root of 21210212 is about 276.8099327352.
The spelling of 21210212 in words is "twenty-one million, two hundred ten thousand, two hundred twelve".