66561575 has 12 divisors (see below), whose sum is σ = 82637568. Its totient is φ = 53184000.

The previous prime is 66561571. The next prime is 66561611. The reversal of 66561575 is 57516566.

It is not a de Polignac number, because 66561575 - 2² = 66561571 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66561571) 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 11 ways as a sum of consecutive naturals, for example, 39194 + ... + 40856.

It is an arithmetic number, because the mean of its divisors is an integer number (6886464).

Almost surely, 2^66561575 is an apocalyptic number.

66561575 is a deficient number, since it is larger than the sum of its proper divisors (16075993).

66561575 is a wasteful number, since it uses less digits than its factorization.

66561575 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3274 (or 3269 counting only the distinct ones).

The product of its digits is 189000, while the sum is 41.

The square root of 66561575 is about 8158.5277470877. The cubic root of 66561575 is about 405.2669580695.

The spelling of 66561575 in words is "sixty-six million, five hundred sixty-one thousand, five hundred seventy-five".