66765899 has 4 divisors (see below), whose sum is σ = 66832440. Its totient is φ = 66699360.

The previous prime is 66765887. The next prime is 66765901. The reversal of 66765899 is 99856766.

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 66765899 - 2⁴ = 66765883 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (66765869) 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, 31742 + ... + 33779.

It is an arithmetic number, because the mean of its divisors is an integer number (16708110).

Almost surely, 2^66765899 is an apocalyptic number.

66765899 is a deficient number, since it is larger than the sum of its proper divisors (66541).

66765899 is a wasteful number, since it uses less digits than its factorization.

66765899 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 66540.

The product of its digits is 4898880, while the sum is 56.

The square root of 66765899 is about 8171.0402642503. The cubic root of 66765899 is about 405.6812169997.

It can be divided in two parts, 667 and 65899, that added together give a palindrome (66566).

The spelling of 66765899 in words is "sixty-six million, seven hundred sixty-five thousand, eight hundred ninety-nine".