11509979 has 4 divisors (see below), whose sum is σ = 12395376. Its totient is φ = 10624584.

The previous prime is 11509973. The next prime is 11509999. The reversal of 11509979 is 97990511.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 97990511 = 23 ⋅4260457.

It is a cyclic number.

It is not a de Polignac number, because 11509979 - 2⁴ = 11509963 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (11509973) 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, 442679 + ... + 442704.

It is an arithmetic number, because the mean of its divisors is an integer number (3098844).

Almost surely, 2^11509979 is an apocalyptic number.

11509979 is a deficient number, since it is larger than the sum of its proper divisors (885397).

11509979 is an equidigital number, since it uses as much as digits as its factorization.

11509979 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 885396.

The product of its (nonzero) digits is 25515, while the sum is 41.

The square root of 11509979 is about 3392.6359958003. The cubic root of 11509979 is about 225.7831409751.

The spelling of 11509979 in words is "eleven million, five hundred nine thousand, nine hundred seventy-nine".