656256217 has 4 divisors (see below), whose sum is σ = 684789120. Its totient is φ = 627723316.

The previous prime is 656256199. The next prime is 656256221. The reversal of 656256217 is 712652656.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 656256217 - 2¹⁹ = 655731929 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 656256217.

It is not an unprimeable number, because it can be changed into a prime (656256917) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 14266417 + ... + 14266462.

It is an arithmetic number, because the mean of its divisors is an integer number (171197280).

Almost surely, 2^656256217 is an apocalyptic number.

It is an amenable number.

656256217 is a deficient number, since it is larger than the sum of its proper divisors (28532903).

656256217 is a wasteful number, since it uses less digits than its factorization.

656256217 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 28532902.

The product of its digits is 151200, while the sum is 40.

The square root of 656256217 is about 25617.4982580267. The cubic root of 656256217 is about 869.0094053980.

The spelling of 656256217 in words is "six hundred fifty-six million, two hundred fifty-six thousand, two hundred seventeen".