21302222221 has 6 divisors (see below), whose sum is σ = 24780136110. Its totient is φ = 18259047576.

The previous prime is 21302222203. The next prime is 21302222251. The reversal of 21302222221 is 12222220312.

It can be written as a sum of positive squares in only one way, i.e., 16093713321 + 5208508900 = 126861^2 + 72170^2 .

It is not a de Polignac number, because 21302222221 - 2¹³ = 21302214029 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21302222251) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 217369566 + ... + 217369663.

It is an arithmetic number, because the mean of its divisors is an integer number (4130022685).

Almost surely, 2^21302222221 is an apocalyptic number.

It is an amenable number.

21302222221 is a deficient number, since it is larger than the sum of its proper divisors (3477913889).

21302222221 is an equidigital number, since it uses as much as digits as its factorization.

21302222221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 434739243 (or 434739236 counting only the distinct ones).

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

Adding to 21302222221 its reverse (12222220312), we get a palindrome (33524442533).

The spelling of 21302222221 in words is "twenty-one billion, three hundred two million, two hundred twenty-two thousand, two hundred twenty-one".