66243967 has 4 divisors (see below), whose sum is σ = 66330880. Its totient is φ = 66157056.

The previous prime is 66243959. The next prime is 66243971. The reversal of 66243967 is 76934266.

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 66243967 - 2³ = 66243959 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 (66243907) 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, 42303 + ... + 43840.

It is an arithmetic number, because the mean of its divisors is an integer number (16582720).

Almost surely, 2^66243967 is an apocalyptic number.

66243967 is a deficient number, since it is larger than the sum of its proper divisors (86913).

66243967 is an equidigital number, since it uses as much as digits as its factorization.

66243967 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 86912.

The product of its digits is 326592, while the sum is 43.

The square root of 66243967 is about 8139.0396853683. The cubic root of 66243967 is about 404.6213338166.

The spelling of 66243967 in words is "sixty-six million, two hundred forty-three thousand, nine hundred sixty-seven".