66718387 has 4 divisors (see below), whose sum is σ = 70643016. Its totient is φ = 62793760.

The previous prime is 66718373. The next prime is 66718397. The reversal of 66718387 is 78381766.

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

It is a cyclic number.

It is not a de Polignac number, because 66718387 - 2¹⁹ = 66194099 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (66718397) 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, 1962289 + ... + 1962322.

It is an arithmetic number, because the mean of its divisors is an integer number (17660754).

Almost surely, 2^66718387 is an apocalyptic number.

66718387 is a deficient number, since it is larger than the sum of its proper divisors (3924629).

66718387 is a wasteful number, since it uses less digits than its factorization.

66718387 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3924628.

The product of its digits is 338688, while the sum is 46.

The square root of 66718387 is about 8168.1324058808. The cubic root of 66718387 is about 405.5849637717.

The spelling of 66718387 in words is "sixty-six million, seven hundred eighteen thousand, three hundred eighty-seven".