217987072 has 48 divisors (see below), whose sum is σ = 439213320. Its totient is φ = 108158976.

The previous prime is 217987067. The next prime is 217987079. The reversal of 217987072 is 270789712.

It is a happy number.

It is a zygodrome in base 2.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (217987079) 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, 333498 + ... + 334150.

Almost surely, 2^217987072 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 217987072, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (219606660).

217987072 is an abundant number, since it is smaller than the sum of its proper divisors (221226248).

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

217987072 is an equidigital number, since it uses as much as digits as its factorization.

217987072 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 838 (or 818 counting only the distinct ones).

The product of its (nonzero) digits is 98784, while the sum is 43.

The square root of 217987072 is about 14764.3852564203. The cubic root of 217987072 is about 601.8342682008.

The spelling of 217987072 in words is "two hundred seventeen million, nine hundred eighty-seven thousand, seventy-two".