66042561 has 16 divisors (see below), whose sum is σ = 95074560. Its totient is φ = 40536960.

The previous prime is 66042553. The next prime is 66042563. The reversal of 66042561 is 16524066.

It is not a de Polignac number, because 66042561 - 2³ = 66042553 is a prime.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (66042563) 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 15 ways as a sum of consecutive naturals, for example, 14845 + ... + 18773.

It is an arithmetic number, because the mean of its divisors is an integer number (5942160).

Almost surely, 2^66042561 is an apocalyptic number.

It is an amenable number.

66042561 is a deficient number, since it is larger than the sum of its proper divisors (29031999).

66042561 is a wasteful number, since it uses less digits than its factorization.

66042561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4376.

The product of its (nonzero) digits is 8640, while the sum is 30.

The square root of 66042561 is about 8126.6574309491. The cubic root of 66042561 is about 404.2108516873.

The spelling of 66042561 in words is "sixty-six million, forty-two thousand, five hundred sixty-one".