11986509 has 4 divisors (see below), whose sum is σ = 15982016. Its totient is φ = 7991004.

The previous prime is 11986493. The next prime is 11986529. The reversal of 11986509 is 90568911.

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 11986509 - 2⁴ = 11986493 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 (11986529) 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, 1997749 + ... + 1997754.

It is an arithmetic number, because the mean of its divisors is an integer number (3995504).

Almost surely, 2^11986509 is an apocalyptic number.

It is an amenable number.

11986509 is a deficient number, since it is larger than the sum of its proper divisors (3995507).

11986509 is an equidigital number, since it uses as much as digits as its factorization.

11986509 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3995506.

The product of its (nonzero) digits is 19440, while the sum is 39.

The square root of 11986509 is about 3462.1538094082. The cubic root of 11986509 is about 228.8570200059.

The spelling of 11986509 in words is "eleven million, nine hundred eighty-six thousand, five hundred nine".