66805069 has 4 divisors (see below), whose sum is σ = 68065596. Its totient is φ = 65544544.

The previous prime is 66805021. The next prime is 66805073. The reversal of 66805069 is 96050866.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 96050866 = 2 ⋅48025433.

It can be written as a sum of positive squares in 2 ways, for example, as 49871844 + 16933225 = 7062^2 + 4115^2 .

It is a cyclic number.

It is not a de Polignac number, because 66805069 - 2²³ = 58416461 is a prime.

It is a super-2 number, since 2×66805069² = 8925834488189522, 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 (66805099) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 630184 + ... + 630289.

It is an arithmetic number, because the mean of its divisors is an integer number (17016399).

Almost surely, 2^66805069 is an apocalyptic number.

It is an amenable number.

66805069 is a deficient number, since it is larger than the sum of its proper divisors (1260527).

66805069 is a wasteful number, since it uses less digits than its factorization.

66805069 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1260526.

The product of its (nonzero) digits is 77760, while the sum is 40.

The square root of 66805069 is about 8173.4367924393. The cubic root of 66805069 is about 405.7605360681.

The spelling of 66805069 in words is "sixty-six million, eight hundred five thousand, sixty-nine".