11901209 has 4 divisors (see below), whose sum is σ = 11934720. Its totient is φ = 11867700.

The previous prime is 11901191. The next prime is 11901217. The reversal of 11901209 is 90210911.

11901209 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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 a cyclic number.

It is not a de Polignac number, because 11901209 - 2¹² = 11897113 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (11901229) 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, 16217 + ... + 16934.

It is an arithmetic number, because the mean of its divisors is an integer number (2983680).

Almost surely, 2^11901209 is an apocalyptic number.

It is an amenable number.

11901209 is a deficient number, since it is larger than the sum of its proper divisors (33511).

11901209 is an equidigital number, since it uses as much as digits as its factorization.

11901209 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 33510.

The product of its (nonzero) digits is 162, while the sum is 23.

The square root of 11901209 is about 3449.8128934770. The cubic root of 11901209 is about 228.3128528111.

The spelling of 11901209 in words is "eleven million, nine hundred one thousand, two hundred nine".