655566217 has 16 divisors (see below), whose sum is σ = 698395392. Its totient is φ = 614053440.

The previous prime is 655566193. The next prime is 655566227. The reversal of 655566217 is 712665556.

It is a de Polignac number, because none of the positive numbers 2^k-655566217 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (655566227) 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 15 ways as a sum of consecutive naturals, for example, 255103 + ... + 257659.

It is an arithmetic number, because the mean of its divisors is an integer number (43649712).

Almost surely, 2^655566217 is an apocalyptic number.

It is an amenable number.

655566217 is a deficient number, since it is larger than the sum of its proper divisors (42829175).

655566217 is a wasteful number, since it uses less digits than its factorization.

655566217 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2808.

The product of its digits is 378000, while the sum is 43.

The square root of 655566217 is about 25604.0273589918. The cubic root of 655566217 is about 868.7047343736.

The spelling of 655566217 in words is "six hundred fifty-five million, five hundred sixty-six thousand, two hundred seventeen".