66018649 has 4 divisors (see below), whose sum is σ = 66035664. Its totient is φ = 66001636.

The previous prime is 66018647. The next prime is 66018709. The reversal of 66018649 is 94681066.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 66018649 - 2¹ = 66018647 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 not an unprimeable number, because it can be changed into a prime (66018643) 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, 474 + ... + 11500.

It is an arithmetic number, because the mean of its divisors is an integer number (16508916).

Almost surely, 2^66018649 is an apocalyptic number.

It is an amenable number.

66018649 is a deficient number, since it is larger than the sum of its proper divisors (17015).

66018649 is a wasteful number, since it uses less digits than its factorization.

66018649 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 17014.

The product of its (nonzero) digits is 62208, while the sum is 40.

The square root of 66018649 is about 8125.1860901766. The cubic root of 66018649 is about 404.1620616520.

The spelling of 66018649 in words is "sixty-six million, eighteen thousand, six hundred forty-nine".