66006665 has 32 divisors (see below), whose sum is σ = 92171520. Its totient is φ = 45010944.

The previous prime is 66006649. The next prime is 66006667. The reversal of 66006665 is 56660066.

66006665 = T₁₁₃₁ + T₁₁₃₂ + ... + T₁₂₂₅.

It is a cyclic number.

It is not a de Polignac number, because 66006665 - 2⁴ = 66006649 is a prime.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (66006667) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 36257 + ... + 38033.

It is an arithmetic number, because the mean of its divisors is an integer number (2880360).

Almost surely, 2^66006665 is an apocalyptic number.

It is an amenable number.

66006665 is a deficient number, since it is larger than the sum of its proper divisors (26164855).

66006665 is a wasteful number, since it uses less digits than its factorization.

66006665 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1841.

The product of its (nonzero) digits is 38880, while the sum is 35.

The square root of 66006665 is about 8124.4485966741. The cubic root of 66006665 is about 404.1376050714.

The spelling of 66006665 in words is "sixty-six million, six thousand, six hundred sixty-five".