21232001321 has 4 divisors (see below), whose sum is σ = 21419895252. Its totient is φ = 21044107392.

The previous prime is 21232001303. The next prime is 21232001359. The reversal of 21232001321 is 12310023212.

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 108576400 + 21123424921 = 10420^2 + 145339^2 .

It is a cyclic number.

It is not a de Polignac number, because 21232001321 - 2³⁴ = 4052132137 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 21232001321.

It is not an unprimeable number, because it can be changed into a prime (21232001221) 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, 93946796 + ... + 93947021.

It is an arithmetic number, because the mean of its divisors is an integer number (5354973813).

Almost surely, 2^21232001321 is an apocalyptic number.

It is an amenable number.

21232001321 is a deficient number, since it is larger than the sum of its proper divisors (187893931).

21232001321 is a wasteful number, since it uses less digits than its factorization.

21232001321 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 187893930.

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

Adding to 21232001321 its reverse (12310023212), we get a palindrome (33542024533).

The spelling of 21232001321 in words is "twenty-one billion, two hundred thirty-two million, one thousand, three hundred twenty-one".