21212021210 has 16 divisors (see below), whose sum is σ = 38193018696. Its totient is φ = 8482279488.

The previous prime is 21212021161. The next prime is 21212021221. The reversal of 21212021210 is 1212021212.

It can be written as a sum of positive squares in 4 ways, for example, as 21089719729 + 122301481 = 145223^2 + 11059^2 .

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, 280709 + ... + 348168.

Almost surely, 2^21212021210 is an apocalyptic number.

21212021210 is a deficient number, since it is larger than the sum of its proper divisors (16980997486).

21212021210 is a wasteful number, since it uses less digits than its factorization.

21212021210 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 632257.

The product of its (nonzero) digits is 32, while the sum is 14.

Adding to 21212021210 its reverse (1212021212), we get a palindrome (22424042422).

The spelling of 21212021210 in words is "twenty-one billion, two hundred twelve million, twenty-one thousand, two hundred ten".