21330231221 has 4 divisors (see below), whose sum is σ = 22971018252. Its totient is φ = 19689444192.

The previous prime is 21330231217. The next prime is 21330231253. The reversal of 21330231221 is 12213203312.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 828000625 + 20502230596 = 28775^2 + 143186^2 .

It is a cyclic number.

It is not a de Polignac number, because 21330231221 - 2² = 21330231217 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21330231193 and 21330231202.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21330231821) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 820393496 + ... + 820393521.

It is an arithmetic number, because the mean of its divisors is an integer number (5742754563).

Almost surely, 2^21330231221 is an apocalyptic number.

It is an amenable number.

21330231221 is a deficient number, since it is larger than the sum of its proper divisors (1640787031).

21330231221 is a wasteful number, since it uses less digits than its factorization.

21330231221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1640787030.

The product of its (nonzero) digits is 432, while the sum is 20.

Adding to 21330231221 its reverse (12213203312), we get a palindrome (33543434533).

The spelling of 21330231221 in words is "twenty-one billion, three hundred thirty million, two hundred thirty-one thousand, two hundred twenty-one".