21212221210 has 16 divisors (see below), whose sum is σ = 39069952416. Its totient is φ = 8287565328.

The previous prime is 21212221193. The next prime is 21212221237. The reversal of 21212221210 is 1212221212.

It is a happy number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 24664944 + ... + 24665803.

It is an arithmetic number, because the mean of its divisors is an integer number (2441872026).

Almost surely, 2^21212221210 is an apocalyptic number.

21212221210 is a deficient number, since it is larger than the sum of its proper divisors (17857731206).

21212221210 is a wasteful number, since it uses less digits than its factorization.

21212221210 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 49330797.

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

Adding to 21212221210 its reverse (1212221212), we get a palindrome (22424442422).

It can be divided in two parts, 212122 and 21210, that added together give a palindrome (233332).

The spelling of 21212221210 in words is "twenty-one billion, two hundred twelve million, two hundred twenty-one thousand, two hundred ten".