656456561 has 4 divisors (see below), whose sum is σ = 658144500. Its totient is φ = 654768624.

The previous prime is 656456543. The next prime is 656456609. The reversal of 656456561 is 165654656.

It is a happy number.

656456561 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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 45427600 + 611028961 = 6740^2 + 24719^2 .

It is a cyclic number.

It is not a de Polignac number, because 656456561 - 2¹⁰ = 656455537 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (656456161) 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, 843386 + ... + 844163.

It is an arithmetic number, because the mean of its divisors is an integer number (164536125).

Almost surely, 2^656456561 is an apocalyptic number.

It is an amenable number.

656456561 is a deficient number, since it is larger than the sum of its proper divisors (1687939).

656456561 is a wasteful number, since it uses less digits than its factorization.

656456561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1687938.

The product of its digits is 648000, while the sum is 44.

The square root of 656456561 is about 25621.4082555975. The cubic root of 656456561 is about 869.0978277256.

The spelling of 656456561 in words is "six hundred fifty-six million, four hundred fifty-six thousand, five hundred sixty-one".