217870845617 has 8 divisors (see below), whose sum is σ = 219264128712. Its totient is φ = 216481792000.

The previous prime is 217870845613. The next prime is 217870845641. The reversal of 217870845617 is 716548078712.

217870845617 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in 4 ways, for example, as 130107375616 + 87763470001 = 360704^2 + 296249^2 .

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 217870845617 - 2² = 217870845613 is a prime.

It is a super-2 number, since 2×217870845617² (a number of 23 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (217870845613) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 953984 + ... + 1160097.

It is an arithmetic number, because the mean of its divisors is an integer number (27408016089).

Almost surely, 2^217870845617 is an apocalyptic number.

It is an amenable number.

217870845617 is a deficient number, since it is larger than the sum of its proper divisors (1393283095).

217870845617 is a wasteful number, since it uses less digits than its factorization.

217870845617 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2114739.

The product of its (nonzero) digits is 5268480, while the sum is 56.

The spelling of 217870845617 in words is "two hundred seventeen billion, eight hundred seventy million, eight hundred forty-five thousand, six hundred seventeen".