216210565 has 4 divisors (see below), whose sum is σ = 259452684. Its totient is φ = 172968448.

The previous prime is 216210529. The next prime is 216210587. The reversal of 216210565 is 565012612.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 157703364 + 58507201 = 12558^2 + 7649^2 .

It is a cyclic number.

It is not a de Polignac number, because 216210565 - 2¹⁹ = 215686277 is a prime.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

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 in 3 ways as a sum of consecutive naturals, for example, 21621052 + ... + 21621061.

It is an arithmetic number, because the mean of its divisors is an integer number (64863171).

Almost surely, 2^216210565 is an apocalyptic number.

It is an amenable number.

216210565 is a deficient number, since it is larger than the sum of its proper divisors (43242119).

216210565 is an equidigital number, since it uses as much as digits as its factorization.

216210565 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 43242118.

The product of its (nonzero) digits is 3600, while the sum is 28.

The square root of 216210565 is about 14704.1002784938. The cubic root of 216210565 is about 600.1949042729.

The spelling of 216210565 in words is "two hundred sixteen million, two hundred ten thousand, five hundred sixty-five".