217105945 has 8 divisors (see below), whose sum is σ = 297745344. Its totient is φ = 148872624.

The previous prime is 217105921. The next prime is 217105949. The reversal of 217105945 is 549501712.

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 217105945 - 2⁷ = 217105817 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 217105945.

It is not an unprimeable number, because it can be changed into a prime (217105949) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 3101479 + ... + 3101548.

It is an arithmetic number, because the mean of its divisors is an integer number (37218168).

Almost surely, 2^217105945 is an apocalyptic number.

It is an amenable number.

217105945 is a deficient number, since it is larger than the sum of its proper divisors (80639399).

217105945 is an equidigital number, since it uses as much as digits as its factorization.

217105945 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6203039.

The product of its (nonzero) digits is 12600, while the sum is 34.

The square root of 217105945 is about 14734.5154314623. The cubic root of 217105945 is about 601.0222803969.

The spelling of 217105945 in words is "two hundred seventeen million, one hundred five thousand, nine hundred forty-five".