66826809 has 32 divisors (see below), whose sum is σ = 115568640. Its totient is φ = 37369296.

The previous prime is 66826789. The next prime is 66826841. The reversal of 66826809 is 90862866.

It is not a de Polignac number, because 66826809 - 2⁷ = 66826681 is a prime.

It is a super-2 number, since 2×66826809² = 8931644802244962, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (66826849) 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 31 ways as a sum of consecutive naturals, for example, 5122 + ... + 12644.

It is an arithmetic number, because the mean of its divisors is an integer number (3611520).

Almost surely, 2^66826809 is an apocalyptic number.

It is an amenable number.

66826809 is a deficient number, since it is larger than the sum of its proper divisors (48741831).

66826809 is a wasteful number, since it uses less digits than its factorization.

66826809 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7586 (or 7580 counting only the distinct ones).

The product of its (nonzero) digits is 248832, while the sum is 45.

The square root of 66826809 is about 8174.7666021728. The cubic root of 66826809 is about 405.8045460885.

The spelling of 66826809 in words is "sixty-six million, eight hundred twenty-six thousand, eight hundred nine".