66318399 has 16 divisors (see below), whose sum is σ = 112285440. Its totient is φ = 37896120.

The previous prime is 66318397. The next prime is 66318451. The reversal of 66318399 is 99381366.

66318399 is a `hidden beast` number, since 6 + 631 + 8 + 3 + 9 + 9 = 666.

It is not a de Polignac number, because 66318399 - 2¹ = 66318397 is a prime.

It is a zygodrome in base 2.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66318391) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 175257 + ... + 175634.

It is an arithmetic number, because the mean of its divisors is an integer number (7017840).

Almost surely, 2^66318399 is an apocalyptic number.

66318399 is a deficient number, since it is larger than the sum of its proper divisors (45967041).

66318399 is a wasteful number, since it uses less digits than its factorization.

66318399 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 350907 (or 350901 counting only the distinct ones).

The product of its digits is 209952, while the sum is 45.

The square root of 66318399 is about 8143.6109312761. The cubic root of 66318399 is about 404.7728218375.

The spelling of 66318399 in words is "sixty-six million, three hundred eighteen thousand, three hundred ninety-nine".