66864207 has 4 divisors (see below), whose sum is σ = 89152280. Its totient is φ = 44576136.

The previous prime is 66864181. The next prime is 66864209. The reversal of 66864207 is 70246866.

It is a semiprime because it is the product of two primes.

It is not a de Polignac number, because 66864207 - 2⁷ = 66864079 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66864209) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 11144032 + ... + 11144037.

It is an arithmetic number, because the mean of its divisors is an integer number (22288070).

Almost surely, 2^66864207 is an apocalyptic number.

66864207 is a deficient number, since it is larger than the sum of its proper divisors (22288073).

66864207 is a wasteful number, since it uses less digits than its factorization.

66864207 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 22288072.

The product of its (nonzero) digits is 96768, while the sum is 39.

The square root of 66864207 is about 8177.0536869951. The cubic root of 66864207 is about 405.8802315233.

The spelling of 66864207 in words is "sixty-six million, eight hundred sixty-four thousand, two hundred seven".