66994809 has 24 divisors (see below), whose sum is σ = 105883200. Its totient is φ = 37556064.

The previous prime is 66994799. The next prime is 66994831. The reversal of 66994809 is 90849966.

It is not a de Polignac number, because 66994809 - 2⁵ = 66994777 is a prime.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (66994709) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 3492 + ... + 12090.

It is an arithmetic number, because the mean of its divisors is an integer number (4411800).

Almost surely, 2^66994809 is an apocalyptic number.

It is an amenable number.

66994809 is a deficient number, since it is larger than the sum of its proper divisors (38888391).

66994809 is a wasteful number, since it uses less digits than its factorization.

66994809 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8669 (or 8662 counting only the distinct ones).

The product of its (nonzero) digits is 839808, while the sum is 51.

The square root of 66994809 is about 8185.0356749375. The cubic root of 66994809 is about 406.1443204721.

The spelling of 66994809 in words is "sixty-six million, nine hundred ninety-four thousand, eight hundred nine".