21202220121 has 8 divisors (see below), whose sum is σ = 28338747360. Its totient is φ = 14100253152.

The previous prime is 21202220077. The next prime is 21202220183. The reversal of 21202220121 is 12102220212.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 21202220121 - 2⁷ = 21202219993 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21202220121.

It is not an unprimeable number, because it can be changed into a prime (21202227121) by changing a digit.

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, 8638635 + ... + 8641088.

It is an arithmetic number, because the mean of its divisors is an integer number (3542343420).

Almost surely, 2^21202220121 is an apocalyptic number.

It is an amenable number.

21202220121 is a deficient number, since it is larger than the sum of its proper divisors (7136527239).

21202220121 is a wasteful number, since it uses less digits than its factorization.

21202220121 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 17280135.

The product of its (nonzero) digits is 64, while the sum is 15.

Adding to 21202220121 its reverse (12102220212), we get a palindrome (33304440333).

Subtracting from 21202220121 its reverse (12102220212), we obtain a palindrome (9099999909).

The spelling of 21202220121 in words is "twenty-one billion, two hundred two million, two hundred twenty thousand, one hundred twenty-one".