21013323221 has 4 divisors (see below), whose sum is σ = 22923625344. Its totient is φ = 19103021100.

The previous prime is 21013323187. The next prime is 21013323223. The reversal of 21013323221 is 12232331012.

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-21013323221 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21013323193 and 21013323202.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21013323223) 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, 955151045 + ... + 955151066.

It is an arithmetic number, because the mean of its divisors is an integer number (5730906336).

Almost surely, 2^21013323221 is an apocalyptic number.

It is an amenable number.

21013323221 is a deficient number, since it is larger than the sum of its proper divisors (1910302123).

21013323221 is a wasteful number, since it uses less digits than its factorization.

21013323221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1910302122.

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

Adding to 21013323221 its reverse (12232331012), we get a palindrome (33245654233).

The spelling of 21013323221 in words is "twenty-one billion, thirteen million, three hundred twenty-three thousand, two hundred twenty-one".