1166605509 has 4 divisors (see below), whose sum is σ = 1555474016. Its totient is φ = 777737004.

The previous prime is 1166605499. The next prime is 1166605519. The reversal of 1166605509 is 9055066611.

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 an interprime number because it is at equal distance from previous prime (1166605499) and next prime (1166605519).

It is not a de Polignac number, because 1166605509 - 2⁵ = 1166605477 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 (1166605519) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 194434249 + ... + 194434254.

It is an arithmetic number, because the mean of its divisors is an integer number (388868504).

Almost surely, 2^1166605509 is an apocalyptic number.

It is an amenable number.

1166605509 is a deficient number, since it is larger than the sum of its proper divisors (388868507).

1166605509 is an equidigital number, since it uses as much as digits as its factorization.

1166605509 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 388868506.

The product of its (nonzero) digits is 48600, while the sum is 39.

The square root of 1166605509 is about 34155.6072848954. The cubic root of 1166605509 is about 1052.7082043444.

The spelling of 1166605509 in words is "one billion, one hundred sixty-six million, six hundred five thousand, five hundred nine".