11861909 has 4 divisors (see below), whose sum is σ = 12486240. Its totient is φ = 11237580.

The previous prime is 11861887. The next prime is 11861917. The reversal of 11861909 is 90916811.

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, and also an emirpimes, since its reverse is a distinct semiprime: 90916811 = 751 ⋅121061.

It is a cyclic number.

It is not a de Polignac number, because 11861909 - 2¹⁶ = 11796373 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (11861959) 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, 312137 + ... + 312174.

It is an arithmetic number, because the mean of its divisors is an integer number (3121560).

Almost surely, 2^11861909 is an apocalyptic number.

11861909 is a gapful number since it is divisible by the number (19) formed by its first and last digit.

It is an amenable number.

11861909 is a deficient number, since it is larger than the sum of its proper divisors (624331).

11861909 is an equidigital number, since it uses as much as digits as its factorization.

11861909 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 624330.

The product of its (nonzero) digits is 3888, while the sum is 35.

The square root of 11861909 is about 3444.1122223296. The cubic root of 11861909 is about 228.0612652125.

The spelling of 11861909 in words is "eleven million, eight hundred sixty-one thousand, nine hundred nine".