21210032321 has 4 divisors (see below), whose sum is σ = 21894226944. Its totient is φ = 20525837700.

The previous prime is 21210032281. The next prime is 21210032341. The reversal of 21210032321 is 12323001212.

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 21210032321 - 2⁶ = 21210032257 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21210032321.

It is not an unprimeable number, because it can be changed into a prime (21210032341) 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, 342097265 + ... + 342097326.

It is an arithmetic number, because the mean of its divisors is an integer number (5473556736).

Almost surely, 2^21210032321 is an apocalyptic number.

It is an amenable number.

21210032321 is a deficient number, since it is larger than the sum of its proper divisors (684194623).

21210032321 is an equidigital number, since it uses as much as digits as its factorization.

21210032321 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 684194622.

The product of its (nonzero) digits is 144, while the sum is 17.

Adding to 21210032321 its reverse (12323001212), we get a palindrome (33533033533).

The spelling of 21210032321 in words is "twenty-one billion, two hundred ten million, thirty-two thousand, three hundred twenty-one".