11521399 has 4 divisors (see below), whose sum is σ = 11533320. Its totient is φ = 11509480.

The previous prime is 11521379. The next prime is 11521421. The reversal of 11521399 is 99312511.

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: 99312511 = 3697 ⋅26863.

It is a cyclic number.

It is not a de Polignac number, because 11521399 - 2¹⁹ = 10997111 is a prime.

It is a Smith number, since the sum of its digits (31) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 11521399.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (11521379) 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, 4369 + ... + 6490.

It is an arithmetic number, because the mean of its divisors is an integer number (2883330).

Almost surely, 2^11521399 is an apocalyptic number.

11521399 is a deficient number, since it is larger than the sum of its proper divisors (11921).

11521399 is a wasteful number, since it uses less digits than its factorization.

11521399 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11920.

The product of its digits is 2430, while the sum is 31.

The square root of 11521399 is about 3394.3186356027. The cubic root of 11521399 is about 225.8577889878.

The spelling of 11521399 in words is "eleven million, five hundred twenty-one thousand, three hundred ninety-nine".