217945087 has 4 divisors (see below), whose sum is σ = 218520520. Its totient is φ = 217369656.

The previous prime is 217945051. The next prime is 217945103. The reversal of 217945087 is 780549712.

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 217945087 - 2⁷ = 217944959 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 (217943087) 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, 287148 + ... + 287905.

It is an arithmetic number, because the mean of its divisors is an integer number (54630130).

Almost surely, 2^217945087 is an apocalyptic number.

217945087 is a deficient number, since it is larger than the sum of its proper divisors (575433).

217945087 is an equidigital number, since it uses as much as digits as its factorization.

217945087 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 575432.

The product of its (nonzero) digits is 141120, while the sum is 43.

The square root of 217945087 is about 14762.9633542863. The cubic root of 217945087 is about 601.7956273249.

The spelling of 217945087 in words is "two hundred seventeen million, nine hundred forty-five thousand, eighty-seven".