1660066509 has 4 divisors (see below), whose sum is σ = 2213422016. Its totient is φ = 1106711004.

The previous prime is 1660066481. The next prime is 1660066511. The reversal of 1660066509 is 9056600661.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is not a de Polignac number, because 1660066509 - 2⁸ = 1660066253 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 (1660066559) 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, 276677749 + ... + 276677754.

It is an arithmetic number, because the mean of its divisors is an integer number (553355504).

Almost surely, 2^1660066509 is an apocalyptic number.

It is an amenable number.

1660066509 is a deficient number, since it is larger than the sum of its proper divisors (553355507).

1660066509 is an equidigital number, since it uses as much as digits as its factorization.

1660066509 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 553355506.

The product of its (nonzero) digits is 58320, while the sum is 39.

The square root of 1660066509 is about 40743.9137663529. The cubic root of 1660066509 is about 1184.0639605563.

The spelling of 1660066509 in words is "one billion, six hundred sixty million, sixty-six thousand, five hundred nine".