213131263561 has 2 divisors, whose sum is σ = 213131263562. Its totient is φ = 213131263560.

The previous prime is 213131263547. The next prime is 213131263573. The reversal of 213131263561 is 165362131312.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 135769403961 + 77361859600 = 368469^2 + 278140^2 .

It is a cyclic number.

It is not a de Polignac number, because 213131263561 - 2⁵ = 213131263529 is a prime.

It is not a weakly prime, because it can be changed into another prime (213131263661) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 106565631780 + 106565631781.

It is an arithmetic number, because the mean of its divisors is an integer number (106565631781).

Almost surely, 2^213131263561 is an apocalyptic number.

It is an amenable number.

213131263561 is a deficient number, since it is larger than the sum of its proper divisors (1).

213131263561 is an equidigital number, since it uses as much as digits as its factorization.

213131263561 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 19440, while the sum is 34.

Adding to 213131263561 its reverse (165362131312), we get a palindrome (378493394873).

The spelling of 213131263561 in words is "two hundred thirteen billion, one hundred thirty-one million, two hundred sixty-three thousand, five hundred sixty-one".