66381165 has 12 divisors (see below), whose sum is σ = 115060764. Its totient is φ = 35403264.

The previous prime is 66381149. The next prime is 66381181. The reversal of 66381165 is 56118366.

It is a happy number.

66381165 is a `hidden beast` number, since 6 + 638 + 1 + 16 + 5 = 666.

It is an interprime number because it is at equal distance from previous prime (66381149) and next prime (66381181).

It can be written as a sum of positive squares in 2 ways, for example, as 47692836 + 18688329 = 6906^2 + 4323^2 .

It is not a de Polignac number, because 66381165 - 2⁴ = 66381149 is a prime.

It is a hoax number, since the sum of its digits (36) coincides with the sum of the digits of its distinct prime factors.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 737524 + ... + 737613.

It is an arithmetic number, because the mean of its divisors is an integer number (9588397).

Almost surely, 2^66381165 is an apocalyptic number.

It is an amenable number.

66381165 is a deficient number, since it is larger than the sum of its proper divisors (48679599).

66381165 is a wasteful number, since it uses less digits than its factorization.

66381165 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1475148 (or 1475145 counting only the distinct ones).

The product of its digits is 25920, while the sum is 36.

The square root of 66381165 is about 8147.4637157830. The cubic root of 66381165 is about 404.9004785185.

The spelling of 66381165 in words is "sixty-six million, three hundred eighty-one thousand, one hundred sixty-five".