660601161560561 has 4 divisors (see below), whose sum is σ = 711416635526772. Its totient is φ = 609785687594352.

The previous prime is 660601161560539. The next prime is 660601161560563. The reversal of 660601161560561 is 165065161106066.

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 242323238560225 + 418277923000336 = 15566735^2 + 20451844^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-660601161560561 is a prime.

It is a super-2 number, since 2×660601161560561² (a number of 30 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (660601161560563) 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, 25407736983086 + ... + 25407736983111.

It is an arithmetic number, because the mean of its divisors is an integer number (177854158881693).

Almost surely, 2^{660601161560561} is an apocalyptic number.

It is an amenable number.

660601161560561 is a deficient number, since it is larger than the sum of its proper divisors (50815473966211).

660601161560561 is a wasteful number, since it uses less digits than its factorization.

660601161560561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 50815473966210.

The product of its (nonzero) digits is 1166400, while the sum is 50.

The spelling of 660601161560561 in words is "six hundred sixty trillion, six hundred one billion, one hundred sixty-one million, five hundred sixty thousand, five hundred sixty-one".