66706669 has 4 divisors (see below), whose sum is σ = 66770140. Its totient is φ = 66643200.

The previous prime is 66706667. The next prime is 66706687. The reversal of 66706669 is 96660766.

It is a happy number.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 51984100 + 14722569 = 7210^2 + 3837^2 .

It is a cyclic number.

It is not a de Polignac number, because 66706669 - 2¹ = 66706667 is a prime.

It is a super-2 number, since 2×66706669² = 8899559378151122, 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 (66706667) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 30132 + ... + 32269.

It is an arithmetic number, because the mean of its divisors is an integer number (16692535).

Almost surely, 2^66706669 is an apocalyptic number.

It is an amenable number.

66706669 is a deficient number, since it is larger than the sum of its proper divisors (63471).

66706669 is a wasteful number, since it uses less digits than its factorization.

66706669 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 63470.

The product of its (nonzero) digits is 489888, while the sum is 46.

The square root of 66706669 is about 8167.4150745508. The cubic root of 66706669 is about 405.5612175797.

The spelling of 66706669 in words is "sixty-six million, seven hundred six thousand, six hundred sixty-nine".