66081509 has 8 divisors (see below), whose sum is σ = 71709792. Its totient is φ = 60531120.

The previous prime is 66081493. The next prime is 66081511. The reversal of 66081509 is 90518066.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 66081509 - 2⁴ = 66081493 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66081559) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 17699 + ... + 21104.

It is an arithmetic number, because the mean of its divisors is an integer number (8963724).

Almost surely, 2^66081509 is an apocalyptic number.

It is an amenable number.

66081509 is a deficient number, since it is larger than the sum of its proper divisors (5628283).

66081509 is a wasteful number, since it uses less digits than its factorization.

66081509 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 38947.

The product of its (nonzero) digits is 12960, while the sum is 35.

The square root of 66081509 is about 8129.0533889254. The cubic root of 66081509 is about 404.2902959640.

The spelling of 66081509 in words is "sixty-six million, eighty-one thousand, five hundred nine".