21233012321 has 4 divisors (see below), whose sum is σ = 21236732052. Its totient is φ = 21229292592.

The previous prime is 21233012233. The next prime is 21233012347. The reversal of 21233012321 is 12321033212.

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 4056288721 + 17176723600 = 63689^2 + 131060^2 .

It is a cyclic number.

It is not a de Polignac number, because 21233012321 - 2¹⁸ = 21232750177 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21233012293 and 21233012302.

It is not an unprimeable number, because it can be changed into a prime (21233012351) 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, 1851290 + ... + 1862723.

It is an arithmetic number, because the mean of its divisors is an integer number (5309183013).

Almost surely, 2^21233012321 is an apocalyptic number.

It is an amenable number.

21233012321 is a deficient number, since it is larger than the sum of its proper divisors (3719731).

21233012321 is an equidigital number, since it uses as much as digits as its factorization.

21233012321 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3719730.

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

Adding to 21233012321 its reverse (12321033212), we get a palindrome (33554045533).

The spelling of 21233012321 in words is "twenty-one billion, two hundred thirty-three million, twelve thousand, three hundred twenty-one".