66649423 has 4 divisors (see below), whose sum is σ = 69547248. Its totient is φ = 63751600.

The previous prime is 66649421. The next prime is 66649433. The reversal of 66649423 is 32494666.

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 66649423 - 2¹ = 66649421 is a prime.

It is a Smith number, since the sum of its digits (40) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66649421) 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, 1448878 + ... + 1448923.

It is an arithmetic number, because the mean of its divisors is an integer number (17386812).

Almost surely, 2^66649423 is an apocalyptic number.

66649423 is a deficient number, since it is larger than the sum of its proper divisors (2897825).

66649423 is a wasteful number, since it uses less digits than its factorization.

66649423 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2897824.

The product of its digits is 186624, while the sum is 40.

The square root of 66649423 is about 8163.9097863707. The cubic root of 66649423 is about 405.4451702023.

The spelling of 66649423 in words is "sixty-six million, six hundred forty-nine thousand, four hundred twenty-three".