66617509653523 has 16 divisors (see below), whose sum is σ = 68504776964064. Its totient is φ = 64734830138880.

The previous prime is 66617509653511. The next prime is 66617509653587. The reversal of 66617509653523 is 32535690571666.

It is a cyclic number.

It is not a de Polignac number, because 66617509653523 - 2⁴⁵ = 31433137564691 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (66617509653923) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 251418636 + ... + 251683462.

It is an arithmetic number, because the mean of its divisors is an integer number (4281548560254).

Almost surely, 2^{66617509653523} is an apocalyptic number.

66617509653523 is a deficient number, since it is larger than the sum of its proper divisors (1887267310541).

66617509653523 is a wasteful number, since it uses less digits than its factorization.

66617509653523 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 273462.

The product of its (nonzero) digits is 183708000, while the sum is 64.

The spelling of 66617509653523 in words is "sixty-six trillion, six hundred seventeen billion, five hundred nine million, six hundred fifty-three thousand, five hundred twenty-three".