11509978 has 4 divisors (see below), whose sum is σ = 17264970. Its totient is φ = 5754988.

The previous prime is 11509973. The next prime is 11509999. The reversal of 11509978 is 87990511.

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: 87990511 = 7 ⋅12570073.

It can be written as a sum of positive squares in only one way, i.e., 10712529 + 797449 = 3273^2 + 893^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 11509978.

It is not an unprimeable number, because it can be changed into a prime (11509973) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 2877493 + ... + 2877496.

Almost surely, 2^11509978 is an apocalyptic number.

11509978 is a deficient number, since it is larger than the sum of its proper divisors (5754992).

11509978 is an equidigital number, since it uses as much as digits as its factorization.

11509978 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5754991.

The product of its (nonzero) digits is 22680, while the sum is 40.

The square root of 11509978 is about 3392.6358484223. The cubic root of 11509978 is about 225.7831344363.

The spelling of 11509978 in words is "eleven million, five hundred nine thousand, nine hundred seventy-eight".