66309869 has 4 divisors (see below), whose sum is σ = 66896796. Its totient is φ = 65722944.

The previous prime is 66309857. The next prime is 66309871. The reversal of 66309869 is 96890366.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 96890366 = 2 ⋅48445183.

It can be written as a sum of positive squares in 2 ways, for example, as 15015625 + 51294244 = 3875^2 + 7162^2 .

It is a cyclic number.

It is not a de Polignac number, because 66309869 - 2¹² = 66305773 is a prime.

It is a super-2 number, since 2×66309869² = 8793997453594322, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66303869) 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, 293294 + ... + 293519.

It is an arithmetic number, because the mean of its divisors is an integer number (16724199).

Almost surely, 2^66309869 is an apocalyptic number.

It is an amenable number.

66309869 is a deficient number, since it is larger than the sum of its proper divisors (586927).

66309869 is a wasteful number, since it uses less digits than its factorization.

66309869 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 586926.

The product of its (nonzero) digits is 419904, while the sum is 47.

The square root of 66309869 is about 8143.0871909860. The cubic root of 66309869 is about 404.7554668738.

The spelling of 66309869 in words is "sixty-six million, three hundred nine thousand, eight hundred sixty-nine".