660656601565 has 4 divisors (see below), whose sum is σ = 792787921884. Its totient is φ = 528525281248.

The previous prime is 660656601523. The next prime is 660656601593. The reversal of 660656601565 is 565106656066.

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 321576323929 + 339080277636 = 567077^2 + 582306^2 .

It is a cyclic number.

It is not a de Polignac number, because 660656601565 - 2²¹ = 660654504413 is a prime.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 66065660152 + ... + 66065660161.

It is an arithmetic number, because the mean of its divisors is an integer number (198196980471).

Almost surely, 2^660656601565 is an apocalyptic number.

It is an amenable number.

660656601565 is a deficient number, since it is larger than the sum of its proper divisors (132131320319).

660656601565 is a wasteful number, since it uses less digits than its factorization.

660656601565 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 132131320318.

The product of its (nonzero) digits is 5832000, while the sum is 52.

The spelling of 660656601565 in words is "six hundred sixty billion, six hundred fifty-six million, six hundred one thousand, five hundred sixty-five".