66445247 has 4 divisors (see below), whose sum is σ = 72485736. Its totient is φ = 60404760.

The previous prime is 66445237. The next prime is 66445259. The reversal of 66445247 is 74254466.

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 66445247 - 2¹⁰ = 66444223 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 66445247.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66445217) 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, 3020228 + ... + 3020249.

It is an arithmetic number, because the mean of its divisors is an integer number (18121434).

Almost surely, 2^66445247 is an apocalyptic number.

66445247 is a deficient number, since it is larger than the sum of its proper divisors (6040489).

66445247 is a wasteful number, since it uses less digits than its factorization.

66445247 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6040488.

The product of its digits is 161280, while the sum is 38.

The square root of 66445247 is about 8151.3954020155. The cubic root of 66445247 is about 405.0307287562.

The spelling of 66445247 in words is "sixty-six million, four hundred forty-five thousand, two hundred forty-seven".