21200220121 has 4 divisors (see below), whose sum is σ = 22316021200. Its totient is φ = 20084419044.

The previous prime is 21200220113. The next prime is 21200220131. The reversal of 21200220121 is 12102200212.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 21200220121 - 2³ = 21200220113 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21200220101) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 557900511 + ... + 557900548.

It is an arithmetic number, because the mean of its divisors is an integer number (5579005300).

Almost surely, 2^21200220121 is an apocalyptic number.

It is an amenable number.

21200220121 is a deficient number, since it is larger than the sum of its proper divisors (1115801079).

21200220121 is a wasteful number, since it uses less digits than its factorization.

21200220121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1115801078.

The product of its (nonzero) digits is 32, while the sum is 13.

Adding to 21200220121 its reverse (12102200212), we get a palindrome (33302420333).

The spelling of 21200220121 in words is "twenty-one billion, two hundred million, two hundred twenty thousand, one hundred twenty-one".