217481216 has 32 divisors (see below), whose sum is σ = 435021330. Its totient is φ = 108724224.

The previous prime is 217481197. The next prime is 217481219. The reversal of 217481216 is 612184712.

It is a happy number.

It can be written as a sum of positive squares in only one way, i.e., 216678400 + 802816 = 14720^2 + 896^2 .

It is a tau number, because it is divible by the number of its divisors (32).

It is a Harshad number since it is a multiple of its sum of digits (32).

It is not an unprimeable number, because it can be changed into a prime (217481219) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 29450 + ... + 36086.

Almost surely, 2^217481216 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 217481216, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (217510665).

217481216 is an abundant number, since it is smaller than the sum of its proper divisors (217540114).

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

217481216 is an frugal number, since it uses more digits than its factorization.

217481216 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6667 (or 6639 counting only the distinct ones).

The product of its digits is 5376, while the sum is 32.

The square root of 217481216 is about 14747.2443527596. The cubic root of 217481216 is about 601.3683731819.

The spelling of 217481216 in words is "two hundred seventeen million, four hundred eighty-one thousand, two hundred sixteen".