216644287 has 8 divisors (see below), whose sum is σ = 227927952. Its totient is φ = 205646400.

The previous prime is 216644279. The next prime is 216644303. The reversal of 216644287 is 782446612.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 216644287 - 2³ = 216644279 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (216644227) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 69889 + ... + 72922.

It is an arithmetic number, because the mean of its divisors is an integer number (28490994).

Almost surely, 2^216644287 is an apocalyptic number.

216644287 is a deficient number, since it is larger than the sum of its proper divisors (11283665).

216644287 is a wasteful number, since it uses less digits than its factorization.

216644287 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 142889.

The product of its digits is 129024, while the sum is 40.

The square root of 216644287 is about 14718.8412247704. The cubic root of 216644287 is about 600.5959698742.

The spelling of 216644287 in words is "two hundred sixteen million, six hundred forty-four thousand, two hundred eighty-seven".