66389765 has 8 divisors (see below), whose sum is σ = 85796088. Its totient is φ = 49026240.

The previous prime is 66389759. The next prime is 66389773. The reversal of 66389765 is 56798366.

66389765 = 5761² + 5762².

66389765 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in 4 ways, for example, as 4153444 + 62236321 = 2038^2 + 7889^2 .

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

It is not a de Polignac number, because 66389765 - 2⁴ = 66389749 is a prime.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 510626 + ... + 510755.

It is an arithmetic number, because the mean of its divisors is an integer number (10724511).

Almost surely, 2^66389765 is an apocalyptic number.

66389765 is a gapful number since it is divisible by the number (65) formed by its first and last digit.

66389765 is the 5762-nd centered square number.

It is an amenable number.

66389765 is a deficient number, since it is larger than the sum of its proper divisors (19406323).

66389765 is a wasteful number, since it uses less digits than its factorization.

66389765 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1021399.

The product of its digits is 1632960, while the sum is 50.

The square root of 66389765 is about 8147.9914702950. The cubic root of 66389765 is about 404.9179633665.

The spelling of 66389765 in words is "sixty-six million, three hundred eighty-nine thousand, seven hundred sixty-five".