217280447 has 4 divisors (see below), whose sum is σ = 228716280. Its totient is φ = 205844616.

The previous prime is 217280431. The next prime is 217280473. The reversal of 217280447 is 744082712.

It is a happy number.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 217280447 - 2⁴ = 217280431 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 (217280477) 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, 5717888 + ... + 5717925.

It is an arithmetic number, because the mean of its divisors is an integer number (57179070).

Almost surely, 2^217280447 is an apocalyptic number.

217280447 is a deficient number, since it is larger than the sum of its proper divisors (11435833).

217280447 is a wasteful number, since it uses less digits than its factorization.

217280447 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11435832.

The product of its (nonzero) digits is 25088, while the sum is 35.

The square root of 217280447 is about 14740.4357805324. The cubic root of 217280447 is about 601.1832640172.

The spelling of 217280447 in words is "two hundred seventeen million, two hundred eighty thousand, four hundred forty-seven".