66128165 has 8 divisors (see below), whose sum is σ = 80056728. Its totient is φ = 52433920.

The previous prime is 66128143. The next prime is 66128191. The reversal of 66128165 is 56182166.

66128165 = T₁₇₃ + T₁₇₄ + ... + T₇₃₇.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 47524 + 66080641 = 218^2 + 8129^2 .

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

It is not a de Polignac number, because 66128165 - 2²⁰ = 65079589 is a prime.

It is a Duffinian number.

It is a Curzon number.

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, 57956 + ... + 59085.

It is an arithmetic number, because the mean of its divisors is an integer number (10007091).

Almost surely, 2^66128165 is an apocalyptic number.

It is an amenable number.

66128165 is a deficient number, since it is larger than the sum of its proper divisors (13928563).

66128165 is a wasteful number, since it uses less digits than its factorization.

66128165 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 117159.

The product of its digits is 17280, while the sum is 35.

The square root of 66128165 is about 8131.9225894004. The cubic root of 66128165 is about 404.3854215690.

The spelling of 66128165 in words is "sixty-six million, one hundred twenty-eight thousand, one hundred sixty-five".