216815239 has 2 divisors, whose sum is σ = 216815240. Its totient is φ = 216815238.

The previous prime is 216815237. The next prime is 216815243. The reversal of 216815239 is 932518612.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 216815239 - 2¹ = 216815237 is a prime.

Together with 216815237, it forms a pair of twin primes.

It is a junction number, because it is equal to n+sod(n) for n = 216815198 and 216815207.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (216815237) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 108407619 + 108407620.

It is an arithmetic number, because the mean of its divisors is an integer number (108407620).

Almost surely, 2^216815239 is an apocalyptic number.

216815239 is a deficient number, since it is larger than the sum of its proper divisors (1).

216815239 is an equidigital number, since it uses as much as digits as its factorization.

216815239 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 25920, while the sum is 37.

The square root of 216815239 is about 14724.6473302419. The cubic root of 216815239 is about 600.7539032457.

The spelling of 216815239 in words is "two hundred sixteen million, eight hundred fifteen thousand, two hundred thirty-nine".