66156506617 has 8 divisors (see below), whose sum is σ = 66877579080. Its totient is φ = 65436729600.

The previous prime is 66156506557. The next prime is 66156506623. The reversal of 66156506617 is 71660565166.

It can be written as a sum of positive squares in 4 ways, for example, as 11215021801 + 54941484816 = 105901^2 + 234396^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 66156506617 - 2³¹ = 64009022969 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (66156506677) by changing a digit.

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 7 ways as a sum of consecutive naturals, for example, 220992 + ... + 425617.

It is an arithmetic number, because the mean of its divisors is an integer number (8359697385).

Almost surely, 2^66156506617 is an apocalyptic number.

It is an amenable number.

66156506617 is a deficient number, since it is larger than the sum of its proper divisors (721072463).

66156506617 is a wasteful number, since it uses less digits than its factorization.

66156506617 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 647723.

The product of its (nonzero) digits is 1360800, while the sum is 49.

The spelling of 66156506617 in words is "sixty-six billion, one hundred fifty-six million, five hundred six thousand, six hundred seventeen".