21200121210 has 32 divisors (see below), whose sum is σ = 50928232320. Its totient is φ = 5648038848.

The previous prime is 21200121203. The next prime is 21200121221. The reversal of 21200121210 is 1212100212.

It is a Curzon number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 300505 + ... + 364284.

It is an arithmetic number, because the mean of its divisors is an integer number (1591507260).

Almost surely, 2^21200121210 is an apocalyptic number.

21200121210 is an abundant number, since it is smaller than the sum of its proper divisors (29728111110).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21200121210 is a wasteful number, since it uses less digits than its factorization.

21200121210 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 665862.

The product of its (nonzero) digits is 16, while the sum is 12.

Adding to 21200121210 its reverse (1212100212), we get a palindrome (22412221422).

The spelling of 21200121210 in words is "twenty-one billion, two hundred million, one hundred twenty-one thousand, two hundred ten".