66616520166157 has 4 divisors (see below), whose sum is σ = 71740867871260. Its totient is φ = 61492172461056.

The previous prime is 66616520166143. The next prime is 66616520166167. The reversal of 66616520166157 is 75166102561666.

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 13141538515876 + 53474981650281 = 3625126^2 + 7312659^2 .

It is a cyclic number.

It is not a de Polignac number, because 66616520166157 - 2¹¹ = 66616520164109 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66616520166107) 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, 2562173852532 + ... + 2562173852557.

It is an arithmetic number, because the mean of its divisors is an integer number (17935216967815).

Almost surely, 2^{66616520166157} is an apocalyptic number.

It is an amenable number.

66616520166157 is a deficient number, since it is larger than the sum of its proper divisors (5124347705103).

66616520166157 is a wasteful number, since it uses less digits than its factorization.

66616520166157 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5124347705102.

The product of its (nonzero) digits is 16329600, while the sum is 58.

The spelling of 66616520166157 in words is "sixty-six trillion, six hundred sixteen billion, five hundred twenty million, one hundred sixty-six thousand, one hundred fifty-seven".