66865817 has 8 divisors (see below), whose sum is σ = 68538624. Its totient is φ = 65198448.

The previous prime is 66865787. The next prime is 66865831. The reversal of 66865817 is 71856866.

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

It is a cyclic number.

It is not a de Polignac number, because 66865817 - 2⁶ = 66865753 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (66865847) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 35768 + ... + 37590.

It is an arithmetic number, because the mean of its divisors is an integer number (8567328).

Almost surely, 2^66865817 is an apocalyptic number.

It is an amenable number.

66865817 is a deficient number, since it is larger than the sum of its proper divisors (1672807).

66865817 is a wasteful number, since it uses less digits than its factorization.

66865817 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2719.

The product of its digits is 483840, while the sum is 47.

The square root of 66865817 is about 8177.1521326193. The cubic root of 66865817 is about 405.8834891802.

The spelling of 66865817 in words is "sixty-six million, eight hundred sixty-five thousand, eight hundred seventeen".