216523 has 2 divisors, whose sum is σ = 216524. Its totient is φ = 216522.

The previous prime is 216509. The next prime is 216551. The reversal of 216523 is 325612.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 216523 - 2¹⁷ = 85451 is a prime.

It is an alternating number because its digits alternate between even and odd.

216523 is a lucky number.

It is equal to p₁₉₃₂₄ and since 216523 and 19324 have the same sum of digits, it is a Honaker prime.

It is a self number, because there is not a number n which added to its sum of digits gives 216523.

It is not a weakly prime, because it can be changed into another prime (216553) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 108261 + 108262.

It is an arithmetic number, because the mean of its divisors is an integer number (108262).

2²¹⁶⁵²³ is an apocalyptic number.

216523 is a deficient number, since it is larger than the sum of its proper divisors (1).

216523 is an equidigital number, since it uses as much as digits as its factorization.

216523 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 360, while the sum is 19.

The square root of 216523 is about 465.3203197798. The cubic root of 216523 is about 60.0483868939.

The spelling of 216523 in words is "two hundred sixteen thousand, five hundred twenty-three".