66906569 has 4 divisors (see below), whose sum is σ = 68003460. Its totient is φ = 65809680.

The previous prime is 66906533. The next prime is 66906589. The reversal of 66906569 is 96560966.

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 21855625 + 45050944 = 4675^2 + 6712^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-66906569 is a prime.

It is a super-2 number, since 2×66906569² = 8952977950703522, which contains 22 as substring.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (66906529) 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 3 ways as a sum of consecutive naturals, for example, 548354 + ... + 548475.

It is an arithmetic number, because the mean of its divisors is an integer number (17000865).

Almost surely, 2^66906569 is an apocalyptic number.

It is an amenable number.

66906569 is a deficient number, since it is larger than the sum of its proper divisors (1096891).

66906569 is a wasteful number, since it uses less digits than its factorization.

66906569 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1096890.

The product of its (nonzero) digits is 524880, while the sum is 47.

The square root of 66906569 is about 8179.6435741418. The cubic root of 66906569 is about 405.9659289357.

The spelling of 66906569 in words is "sixty-six million, nine hundred six thousand, five hundred sixty-nine".