66299609 has 4 divisors (see below), whose sum is σ = 70199604. Its totient is φ = 62399616.

The previous prime is 66299591. The next prime is 66299617. The reversal of 66299609 is 90699266.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 54760000 + 11539609 = 7400^2 + 3397^2 .

It is a cyclic number.

It is not a de Polignac number, because 66299609 - 2¹² = 66295513 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 (66299659) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1949972 + ... + 1950005.

It is an arithmetic number, because the mean of its divisors is an integer number (17549901).

Almost surely, 2^66299609 is an apocalyptic number.

It is an amenable number.

66299609 is a deficient number, since it is larger than the sum of its proper divisors (3899995).

66299609 is a wasteful number, since it uses less digits than its factorization.

66299609 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3899994.

The product of its (nonzero) digits is 314928, while the sum is 47.

The square root of 66299609 is about 8142.4571844131. The cubic root of 66299609 is about 404.7345901157.

The spelling of 66299609 in words is "sixty-six million, two hundred ninety-nine thousand, six hundred nine".