66316815 has 24 divisors (see below), whose sum is σ = 115605360. Its totient is φ = 35167104.

The previous prime is 66316759. The next prime is 66316819. The reversal of 66316815 is 51861366.

It is a happy number.

66316815 is a `hidden beast` number, since 6 + 631 + 6 + 8 + 15 = 666.

It is not a de Polignac number, because 66316815 - 2⁸ = 66316559 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 66316815.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66316819) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 3939 + ... + 12171.

It is an arithmetic number, because the mean of its divisors is an integer number (4816890).

Almost surely, 2^66316815 is an apocalyptic number.

66316815 is a deficient number, since it is larger than the sum of its proper divisors (49288545).

66316815 is a wasteful number, since it uses less digits than its factorization.

66316815 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8423 (or 8420 counting only the distinct ones).

The product of its digits is 25920, while the sum is 36.

The square root of 66316815 is about 8143.5136765404. The cubic root of 66316815 is about 404.7695991760.

The spelling of 66316815 in words is "sixty-six million, three hundred sixteen thousand, eight hundred fifteen".