216505633 has 4 divisors (see below), whose sum is σ = 220175280. Its totient is φ = 212835988.

The previous prime is 216505631. The next prime is 216505657. The reversal of 216505633 is 336505612.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 216505633 - 2¹ = 216505631 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 216505595 and 216505604.

It is not an unprimeable number, because it can be changed into a prime (216505631) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1834735 + ... + 1834852.

It is an arithmetic number, because the mean of its divisors is an integer number (55043820).

Almost surely, 2^216505633 is an apocalyptic number.

It is an amenable number.

216505633 is a deficient number, since it is larger than the sum of its proper divisors (3669647).

216505633 is an equidigital number, since it uses as much as digits as its factorization.

216505633 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3669646.

The product of its (nonzero) digits is 16200, while the sum is 31.

The square root of 216505633 is about 14714.1303854492. The cubic root of 216505633 is about 600.4678138592.

The spelling of 216505633 in words is "two hundred sixteen million, five hundred five thousand, six hundred thirty-three".