66385891 has 8 divisors (see below), whose sum is σ = 77991984. Its totient is φ = 55708320.

The previous prime is 66385883. The next prime is 66385919. The reversal of 66385891 is 19858366.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 66385891 - 2³ = 66385883 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (66385801) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 231976 + ... + 232261.

It is an arithmetic number, because the mean of its divisors is an integer number (9748998).

Almost surely, 2^66385891 is an apocalyptic number.

66385891 is a deficient number, since it is larger than the sum of its proper divisors (11606093).

66385891 is a wasteful number, since it uses less digits than its factorization.

66385891 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 464261.

The product of its digits is 311040, while the sum is 46.

The square root of 66385891 is about 8147.7537395285. The cubic root of 66385891 is about 404.9100872393.

It can be divided in two parts, 66385 and 891, that added together give a palindrome (67276).

The spelling of 66385891 in words is "sixty-six million, three hundred eighty-five thousand, eight hundred ninety-one".