66404709 has 12 divisors (see below), whose sum is σ = 109620576. Its totient is φ = 37945512.

The previous prime is 66404687. The next prime is 66404743. The reversal of 66404709 is 90740466.

66404709 is a `hidden beast` number, since 6 + 640 + 4 + 7 + 0 + 9 = 666.

It is not a de Polignac number, because 66404709 - 2⁷ = 66404581 is a prime.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66404909) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 526959 + ... + 527084.

It is an arithmetic number, because the mean of its divisors is an integer number (9135048).

Almost surely, 2^66404709 is an apocalyptic number.

It is an amenable number.

66404709 is a deficient number, since it is larger than the sum of its proper divisors (43215867).

66404709 is a wasteful number, since it uses less digits than its factorization.

66404709 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1054056 (or 1054053 counting only the distinct ones).

The product of its (nonzero) digits is 36288, while the sum is 36.

The square root of 66404709 is about 8148.9084545109. The cubic root of 66404709 is about 404.9483427485.

The spelling of 66404709 in words is "sixty-six million, four hundred four thousand, seven hundred nine".