656662857561 has 12 divisors (see below), whose sum is σ = 966409489188. Its totient is φ = 429515327904.

The previous prime is 656662857559. The next prime is 656662857581. The reversal of 656662857561 is 165758266656.

It can be written as a sum of positive squares in 2 ways, for example, as 191069523225 + 465593334336 = 437115^2 + 682344^2 .

It is not a de Polignac number, because 656662857561 - 2¹ = 656662857559 is a prime.

It is a super-2 number, since 2×656662857561² (a number of 24 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (656662857541) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 688325370 + ... + 688326323.

It is an arithmetic number, because the mean of its divisors is an integer number (80534124099).

Almost surely, 2^656662857561 is an apocalyptic number.

It is an amenable number.

656662857561 is a deficient number, since it is larger than the sum of its proper divisors (309746631627).

656662857561 is a wasteful number, since it uses less digits than its factorization.

656662857561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1376651752 (or 1376651749 counting only the distinct ones).

The product of its digits is 108864000, while the sum is 63.

The spelling of 656662857561 in words is "six hundred fifty-six billion, six hundred sixty-two million, eight hundred fifty-seven thousand, five hundred sixty-one".