656478617 has 4 divisors (see below), whose sum is σ = 668865060. Its totient is φ = 644092176.

The previous prime is 656478611. The next prime is 656478619. The reversal of 656478617 is 716874656.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 251825161 + 404653456 = 15869^2 + 20116^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-656478617 is a prime.

It is a super-3 number, since 3×656478617³ (a number of 27 digits) contains 333 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (656478611) 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, 6193142 + ... + 6193247.

It is an arithmetic number, because the mean of its divisors is an integer number (167216265).

Almost surely, 2^656478617 is an apocalyptic number.

It is an amenable number.

656478617 is a deficient number, since it is larger than the sum of its proper divisors (12386443).

656478617 is a wasteful number, since it uses less digits than its factorization.

656478617 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12386442.

The product of its digits is 1693440, while the sum is 50.

The square root of 656478617 is about 25621.8386732881. The cubic root of 656478617 is about 869.1075610973.

The spelling of 656478617 in words is "six hundred fifty-six million, four hundred seventy-eight thousand, six hundred seventeen".