216506513 has 2 divisors, whose sum is σ = 216506514. Its totient is φ = 216506512.

The previous prime is 216506483. The next prime is 216506557. The reversal of 216506513 is 315605612.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 184334929 + 32171584 = 13577^2 + 5672^2 .

It is a cyclic number.

It is not a de Polignac number, because 216506513 - 2¹² = 216502417 is a prime.

It is not a weakly prime, because it can be changed into another prime (216506593) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 108253256 + 108253257.

It is an arithmetic number, because the mean of its divisors is an integer number (108253257).

Almost surely, 2^216506513 is an apocalyptic number.

It is an amenable number.

216506513 is a deficient number, since it is larger than the sum of its proper divisors (1).

216506513 is an equidigital number, since it uses as much as digits as its factorization.

216506513 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 5400, while the sum is 29.

The square root of 216506513 is about 14714.1602886471. The cubic root of 216506513 is about 600.4686274038.

Subtracting 216506513 from its reverse (315605612), we obtain a palindrome (99099099).

The spelling of 216506513 in words is "two hundred sixteen million, five hundred six thousand, five hundred thirteen".