21531322213 has 2 divisors, whose sum is σ = 21531322214. Its totient is φ = 21531322212.

The previous prime is 21531322193. The next prime is 21531322229. The reversal of 21531322213 is 31222313512.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 21442623489 + 88698724 = 146433^2 + 9418^2 .

It is a cyclic number.

It is not a de Polignac number, because 21531322213 - 2¹⁷ = 21531191141 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21531322283) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10765661106 + 10765661107.

It is an arithmetic number, because the mean of its divisors is an integer number (10765661107).

Almost surely, 2^21531322213 is an apocalyptic number.

It is an amenable number.

21531322213 is a deficient number, since it is larger than the sum of its proper divisors (1).

21531322213 is an equidigital number, since it uses as much as digits as its factorization.

21531322213 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 2160, while the sum is 25.

Adding to 21531322213 its reverse (31222313512), we get a palindrome (52753635725).

The spelling of 21531322213 in words is "twenty-one billion, five hundred thirty-one million, three hundred twenty-two thousand, two hundred thirteen".