66643745 has 24 divisors (see below), whose sum is σ = 93142464. Its totient is φ = 44841888.

The previous prime is 66643727. The next prime is 66643747. The reversal of 66643745 is 54734666.

It is not a de Polignac number, because 66643745 - 2¹⁶ = 66578209 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (66643747) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 121562 + ... + 122108.

It is an arithmetic number, because the mean of its divisors is an integer number (3880936).

Almost surely, 2^66643745 is an apocalyptic number.

It is an amenable number.

66643745 is a deficient number, since it is larger than the sum of its proper divisors (26498719).

66643745 is an equidigital number, since it uses as much as digits as its factorization.

66643745 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 677 (or 618 counting only the distinct ones).

The product of its digits is 362880, while the sum is 41.

The square root of 66643745 is about 8163.5620289185. The cubic root of 66643745 is about 405.4336563090.

The spelling of 66643745 in words is "sixty-six million, six hundred forty-three thousand, seven hundred forty-five".