21331330121 has 4 divisors (see below), whose sum is σ = 21331829712. Its totient is φ = 21330830532.

The previous prime is 21331330079. The next prime is 21331330127. The reversal of 21331330121 is 12103313312.

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 a de Polignac number, because none of the positive numbers 2^k-21331330121 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21331330093 and 21331330102.

It is not an unprimeable number, because it can be changed into a prime (21331330127) 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 3 ways as a sum of consecutive naturals, for example, 179075 + ... + 273368.

It is an arithmetic number, because the mean of its divisors is an integer number (5332957428).

Almost surely, 2^21331330121 is an apocalyptic number.

It is an amenable number.

21331330121 is a deficient number, since it is larger than the sum of its proper divisors (499591).

21331330121 is an equidigital number, since it uses as much as digits as its factorization.

21331330121 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 499590.

The product of its (nonzero) digits is 324, while the sum is 20.

Adding to 21331330121 its reverse (12103313312), we get a palindrome (33434643433).

The spelling of 21331330121 in words is "twenty-one billion, three hundred thirty-one million, three hundred thirty thousand, one hundred twenty-one".