66078891 has 6 divisors (see below), whose sum is σ = 95447300. Its totient is φ = 44052588.

The previous prime is 66078853. The next prime is 66078893. The reversal of 66078891 is 19887066.

It is a happy number.

66078891 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is not a de Polignac number, because 66078891 - 2¹⁰ = 66077867 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (66078893) 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 5 ways as a sum of consecutive naturals, for example, 3671041 + ... + 3671058.

Almost surely, 2^66078891 is an apocalyptic number.

66078891 is a deficient number, since it is larger than the sum of its proper divisors (29368409).

66078891 is a wasteful number, since it uses less digits than its factorization.

66078891 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7342105 (or 7342102 counting only the distinct ones).

The product of its (nonzero) digits is 145152, while the sum is 45.

The square root of 66078891 is about 8128.8923599713. The cubic root of 66078891 is about 404.2849568710.

The spelling of 66078891 in words is "sixty-six million, seventy-eight thousand, eight hundred ninety-one".