66617009 has 4 divisors (see below), whose sum is σ = 66910704. Its totient is φ = 66323316.

The previous prime is 66616943. The next prime is 66617017. The reversal of 66617009 is 90071666.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 66617009 - 2¹⁶ = 66551473 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 66617009.

It is not an unprimeable number, because it can be changed into a prime (66617029) by changing a digit.

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 3 ways as a sum of consecutive naturals, for example, 146507 + ... + 146960.

It is an arithmetic number, because the mean of its divisors is an integer number (16727676).

Almost surely, 2^66617009 is an apocalyptic number.

It is an amenable number.

66617009 is a deficient number, since it is larger than the sum of its proper divisors (293695).

66617009 is a wasteful number, since it uses less digits than its factorization.

66617009 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 293694.

The product of its (nonzero) digits is 13608, while the sum is 35.

The square root of 66617009 is about 8161.9243441728. The cubic root of 66617009 is about 405.3794320448.

The spelling of 66617009 in words is "sixty-six million, six hundred seventeen thousand, nine".