66783765 has 32 divisors (see below), whose sum is σ = 116121600. Its totient is φ = 32650560.

The previous prime is 66783749. The next prime is 66783767. The reversal of 66783765 is 56738766.

It is not a de Polignac number, because 66783765 - 2⁴ = 66783749 is a prime.

It is a Smith number, since the sum of its digits (48) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66783767) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 5056 + ... + 12614.

It is an arithmetic number, because the mean of its divisors is an integer number (3628800).

Almost surely, 2^66783765 is an apocalyptic number.

It is an amenable number.

66783765 is a deficient number, since it is larger than the sum of its proper divisors (49337835).

66783765 is a wasteful number, since it uses less digits than its factorization.

66783765 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7617.

The product of its digits is 1270080, while the sum is 48.

The square root of 66783765 is about 8172.1334423760. The cubic root of 66783765 is about 405.7173994138.

The spelling of 66783765 in words is "sixty-six million, seven hundred eighty-three thousand, seven hundred sixty-five".