217288987 has 8 divisors (see below), whose sum is σ = 219241152. Its totient is φ = 215342400.

The previous prime is 217288979. The next prime is 217288991. The reversal of 217288987 is 789882712.

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 217288987 - 2³ = 217288979 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (217288927) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 123937 + ... + 125677.

It is an arithmetic number, because the mean of its divisors is an integer number (27405144).

Almost surely, 2^217288987 is an apocalyptic number.

217288987 is a deficient number, since it is larger than the sum of its proper divisors (1952165).

217288987 is a wasteful number, since it uses less digits than its factorization.

217288987 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2789.

The product of its digits is 903168, while the sum is 52.

The square root of 217288987 is about 14740.7254570459. The cubic root of 217288987 is about 601.1911402249.

The spelling of 217288987 in words is "two hundred seventeen million, two hundred eighty-eight thousand, nine hundred eighty-seven".