66745687 has 4 divisors (see below), whose sum is σ = 68165856. Its totient is φ = 65325520.

The previous prime is 66745681. The next prime is 66745691. The reversal of 66745687 is 78654766.

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 66745687 - 2¹⁹ = 66221399 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 66745687.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66745681) 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, 710014 + ... + 710107.

It is an arithmetic number, because the mean of its divisors is an integer number (17041464).

Almost surely, 2^66745687 is an apocalyptic number.

66745687 is a deficient number, since it is larger than the sum of its proper divisors (1420169).

66745687 is a wasteful number, since it uses less digits than its factorization.

66745687 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1420168.

The product of its digits is 1693440, while the sum is 49.

The square root of 66745687 is about 8169.8033636067. The cubic root of 66745687 is about 405.6402756586.

The spelling of 66745687 in words is "sixty-six million, seven hundred forty-five thousand, six hundred eighty-seven".