21212121110210 has 32 divisors (see below), whose sum is σ = 38929348347120. Its totient is φ = 8320335593472.

The previous prime is 21212121110209. The next prime is 21212121110231. The reversal of 21212121110210 is 1201112121212.

It can be written as a sum of positive squares in 8 ways, for example, as 8236859820049 + 12975261290161 = 2869993^2 + 3602119^2 .

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 100206959 + ... + 100418418.

Almost surely, 2^{21212121110210} is an apocalyptic number.

21212121110210 is a deficient number, since it is larger than the sum of its proper divisors (17717227236910).

21212121110210 is a wasteful number, since it uses less digits than its factorization.

21212121110210 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 200625590.

The product of its (nonzero) digits is 32, while the sum is 17.

Adding to 21212121110210 its reverse (1201112121212), we get a palindrome (22413233231422).

The spelling of 21212121110210 in words is "twenty-one trillion, two hundred twelve billion, one hundred twenty-one million, one hundred ten thousand, two hundred ten".