66078609 has 16 divisors (see below), whose sum is σ = 97345152. Its totient is φ = 39657728.

The previous prime is 66078557. The next prime is 66078629. The reversal of 66078609 is 90687066.

It is a happy number.

66078609 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-66078609 is a prime.

It is not an unprimeable number, because it can be changed into a prime (66078629) by changing a digit.

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 15 ways as a sum of consecutive naturals, for example, 26994 + ... + 29339.

It is an arithmetic number, because the mean of its divisors is an integer number (6084072).

Almost surely, 2^66078609 is an apocalyptic number.

66078609 is a gapful number since it is divisible by the number (69) formed by its first and last digit.

It is an amenable number.

66078609 is a deficient number, since it is larger than the sum of its proper divisors (31266543).

66078609 is a wasteful number, since it uses less digits than its factorization.

66078609 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 56376.

The product of its (nonzero) digits is 108864, while the sum is 42.

The square root of 66078609 is about 8128.8750144162. The cubic root of 66078609 is about 404.2843817578.

The spelling of 66078609 in words is "sixty-six million, seventy-eight thousand, six hundred nine".