66388699 has 4 divisors (see below), whose sum is σ = 71495536. Its totient is φ = 61281864.

The previous prime is 66388697. The next prime is 66388711. The reversal of 66388699 is 99688366.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 66388699 - 2¹ = 66388697 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (66388697) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2553399 + ... + 2553424.

It is an arithmetic number, because the mean of its divisors is an integer number (17873884).

Almost surely, 2^66388699 is an apocalyptic number.

66388699 is a deficient number, since it is larger than the sum of its proper divisors (5106837).

66388699 is a wasteful number, since it uses less digits than its factorization.

66388699 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5106836.

The product of its digits is 3359232, while the sum is 55.

The square root of 66388699 is about 8147.9260551382. The cubic root of 66388699 is about 404.9157961406.

The spelling of 66388699 in words is "sixty-six million, three hundred eighty-eight thousand, six hundred ninety-nine".