217720416 has 24 divisors (see below), whose sum is σ = 571516344. Its totient is φ = 72573440.

The previous prime is 217720397. The next prime is 217720417. The reversal of 217720416 is 614027712.

It is a tau number, because it is divible by the number of its divisors (24).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (217720417) by changing a digit.

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, 1133865 + ... + 1134056.

It is an arithmetic number, because the mean of its divisors is an integer number (23813181).

Almost surely, 2^217720416 is an apocalyptic number.

It is an amenable number.

217720416 is an abundant number, since it is smaller than the sum of its proper divisors (353795928).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

217720416 is a wasteful number, since it uses less digits than its factorization.

217720416 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2267934 (or 2267926 counting only the distinct ones).

The product of its (nonzero) digits is 4704, while the sum is 30.

The square root of 217720416 is about 14755.3521137247. The cubic root of 217720416 is about 601.5887670964.

The spelling of 217720416 in words is "two hundred seventeen million, seven hundred twenty thousand, four hundred sixteen".