66813378 has 16 divisors (see below), whose sum is σ = 133721280. Its totient is φ = 22255376.

The previous prime is 66813377. The next prime is 66813389. The reversal of 66813378 is 87331866.

It is a Smith number, since the sum of its digits (42) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is not an unprimeable number, because it can be changed into a prime (66813377) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 8068 + ... + 14096.

It is an arithmetic number, because the mean of its divisors is an integer number (8357580).

Almost surely, 2^66813378 is an apocalyptic number.

66813378 is an abundant number, since it is smaller than the sum of its proper divisors (66907902).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

66813378 is a wasteful number, since it uses less digits than its factorization.

66813378 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7881.

The product of its digits is 145152, while the sum is 42.

The square root of 66813378 is about 8173.9450695487. The cubic root of 66813378 is about 405.7773577683. Note that the first 3 decimals are identical.

The spelling of 66813378 in words is "sixty-six million, eight hundred thirteen thousand, three hundred seventy-eight".