66645959 has 4 divisors (see below), whose sum is σ = 67394880. Its totient is φ = 65897040.

The previous prime is 66645949. The next prime is 66645983. The reversal of 66645959 is 95954666.

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 66645959 - 2⁸ = 66645703 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66645949) 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 3 ways as a sum of consecutive naturals, for example, 374327 + ... + 374504.

It is an arithmetic number, because the mean of its divisors is an integer number (16848720).

Almost surely, 2^66645959 is an apocalyptic number.

66645959 is a deficient number, since it is larger than the sum of its proper divisors (748921).

66645959 is an equidigital number, since it uses as much as digits as its factorization.

66645959 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 748920.

The product of its digits is 1749600, while the sum is 50.

The square root of 66645959 is about 8163.6976303633. The cubic root of 66645959 is about 405.4381459535.

The spelling of 66645959 in words is "sixty-six million, six hundred forty-five thousand, nine hundred fifty-nine".