66812165 has 16 divisors (see below), whose sum is σ = 93864960. Its totient is φ = 44695680.

The previous prime is 66812149. The next prime is 66812167. The reversal of 66812165 is 56121866.

It is a happy number.

It is not a de Polignac number, because 66812165 - 2⁴ = 66812149 is a prime.

It is a super-3 number, since 3×66812165³ (a number of 24 digits) contains 333 as substring.

It is a Harshad number since it is a multiple of its sum of digits (35).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66812167) 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, 21845 + ... + 24714.

It is an arithmetic number, because the mean of its divisors is an integer number (5866560).

Almost surely, 2^66812165 is an apocalyptic number.

It is an amenable number.

66812165 is a deficient number, since it is larger than the sum of its proper divisors (27052795).

66812165 is a wasteful number, since it uses less digits than its factorization.

66812165 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 46612.

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

The square root of 66812165 is about 8173.8708700346. The cubic root of 66812165 is about 405.7749021179.

The spelling of 66812165 in words is "sixty-six million, eight hundred twelve thousand, one hundred sixty-five".