21013204321 has 2 divisors, whose sum is σ = 21013204322. Its totient is φ = 21013204320.

The previous prime is 21013204241. The next prime is 21013204349. The reversal of 21013204321 is 12340231012.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 20249290000 + 763914321 = 142300^2 + 27639^2 .

It is a cyclic number.

It is not a de Polignac number, because 21013204321 - 2²⁷ = 20878986593 is a prime.

It is not a weakly prime, because it can be changed into another prime (21013204351) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10506602160 + 10506602161.

It is an arithmetic number, because the mean of its divisors is an integer number (10506602161).

Almost surely, 2^21013204321 is an apocalyptic number.

It is an amenable number.

21013204321 is a deficient number, since it is larger than the sum of its proper divisors (1).

21013204321 is an equidigital number, since it uses as much as digits as its factorization.

21013204321 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 288, while the sum is 19.

Adding to 21013204321 its reverse (12340231012), we get a palindrome (33353435333).

The spelling of 21013204321 in words is "twenty-one billion, thirteen million, two hundred four thousand, three hundred twenty-one".