66611555561560 has 32 divisors (see below), whose sum is σ = 149876245490400. Its totient is φ = 26644578584320.

The previous prime is 66611555561539. The next prime is 66611555561671. The reversal of 66611555561560 is 6516555511666.

It is a junction number, because it is equal to n+sod(n) for n = 66611555561495 and 66611555561504.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 36004740 + ... + 37809580.

It is an arithmetic number, because the mean of its divisors is an integer number (4683632671575).

Almost surely, 2^{66611555561560} is an apocalyptic number.

It is an amenable number.

66611555561560 is an abundant number, since it is smaller than the sum of its proper divisors (83264689928840).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

66611555561560 is a wasteful number, since it uses less digits than its factorization.

66611555561560 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2727531 (or 2727527 counting only the distinct ones).

The product of its (nonzero) digits is 24300000, while the sum is 58.

The spelling of 66611555561560 in words is "sixty-six trillion, six hundred eleven billion, five hundred fifty-five million, five hundred sixty-one thousand, five hundred sixty".