11521209 has 8 divisors (see below), whose sum is σ = 17556160. Its totient is φ = 6583536.

The previous prime is 11521199. The next prime is 11521249. The reversal of 11521209 is 90212511.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 11521209 - 2⁹ = 11520697 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (21), and also a Moran number because the ratio is a prime number: 548629 = 11521209 / (1 + 1 + 5 + 2 + 1 + 2 + 0 + 9).

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (11521249) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 274294 + ... + 274335.

It is an arithmetic number, because the mean of its divisors is an integer number (2194520).

Almost surely, 2^11521209 is an apocalyptic number.

It is an amenable number.

11521209 is a deficient number, since it is larger than the sum of its proper divisors (6034951).

11521209 is an equidigital number, since it uses as much as digits as its factorization.

11521209 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 548639.

The product of its (nonzero) digits is 180, while the sum is 21.

The square root of 11521209 is about 3394.2906475433. The cubic root of 11521209 is about 225.8565474367.

The spelling of 11521209 in words is "eleven million, five hundred twenty-one thousand, two hundred nine".