66378969 has 6 divisors (see below), whose sum is σ = 95880746. Its totient is φ = 44252640.

The previous prime is 66378937. The next prime is 66379003. The reversal of 66378969 is 96987366.

It is a happy number.

It can be written as a sum of positive squares in only one way, i.e., 51840000 + 14538969 = 7200^2 + 3813^2 .

It is not a de Polignac number, because 66378969 - 2⁵ = 66378937 is a prime.

It is a super-2 number, since 2×66378969² = 8812335051005922, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (66378569) 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 5 ways as a sum of consecutive naturals, for example, 3687712 + ... + 3687729.

Almost surely, 2^66378969 is an apocalyptic number.

It is an amenable number.

66378969 is a deficient number, since it is larger than the sum of its proper divisors (29501777).

66378969 is a wasteful number, since it uses less digits than its factorization.

66378969 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7375447 (or 7375444 counting only the distinct ones).

The product of its digits is 2939328, while the sum is 54.

The square root of 66378969 is about 8147.3289488028. The cubic root of 66378969 is about 404.8960135408.

The spelling of 66378969 in words is "sixty-six million, three hundred seventy-eight thousand, nine hundred sixty-nine".