21202240321 has 2 divisors, whose sum is σ = 21202240322. Its totient is φ = 21202240320.

The previous prime is 21202240307. The next prime is 21202240337. The reversal of 21202240321 is 12304220212.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 18793393921 + 2408846400 = 137089^2 + 49080^2 .

It is a cyclic number.

It is not a de Polignac number, because 21202240321 - 2⁵ = 21202240289 is a prime.

It is not a weakly prime, because it can be changed into another prime (21202240361) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10601120160 + 10601120161.

It is an arithmetic number, because the mean of its divisors is an integer number (10601120161).

Almost surely, 2^21202240321 is an apocalyptic number.

It is an amenable number.

21202240321 is a deficient number, since it is larger than the sum of its proper divisors (1).

21202240321 is an equidigital number, since it uses as much as digits as its factorization.

21202240321 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 384, while the sum is 19.

Adding to 21202240321 its reverse (12304220212), we get a palindrome (33506460533).

The spelling of 21202240321 in words is "twenty-one billion, two hundred two million, two hundred forty thousand, three hundred twenty-one".