66109669 has 4 divisors (see below), whose sum is σ = 66321196. Its totient is φ = 65898144.

The previous prime is 66109643. The next prime is 66109679. The reversal of 66109669 is 96690166.

66109669 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 96690166 = 2 ⋅48345083.

It can be written as a sum of positive squares in 2 ways, for example, as 580644 + 65529025 = 762^2 + 8095^2 .

It is a cyclic number.

It is not a de Polignac number, because 66109669 - 2⁷ = 66109541 is a prime.

It is a super-2 number, since 2×66109669² = 8740976670579122, 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 (66109609) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 105294 + ... + 105919.

It is an arithmetic number, because the mean of its divisors is an integer number (16580299).

Almost surely, 2^66109669 is an apocalyptic number.

It is an amenable number.

66109669 is a deficient number, since it is larger than the sum of its proper divisors (211527).

66109669 is a wasteful number, since it uses less digits than its factorization.

66109669 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 211526.

The product of its (nonzero) digits is 104976, while the sum is 43.

The square root of 66109669 is about 8130.7852634294. The cubic root of 66109669 is about 404.3477159499.

The spelling of 66109669 in words is "sixty-six million, one hundred nine thousand, six hundred sixty-nine".