11381999 has 4 divisors (see below), whose sum is σ = 11408136. Its totient is φ = 11355864.

The previous prime is 11381989. The next prime is 11382011. The reversal of 11381999 is 99918311.

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: 99918311 = 29 ⋅3445459.

It is a cyclic number.

It is not a de Polignac number, because 11381999 - 2⁴ = 11381983 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (11381989) 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, 12404 + ... + 13289.

It is an arithmetic number, because the mean of its divisors is an integer number (2852034).

Almost surely, 2^11381999 is an apocalyptic number.

11381999 is a deficient number, since it is larger than the sum of its proper divisors (26137).

11381999 is an equidigital number, since it uses as much as digits as its factorization.

11381999 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 26136.

The product of its digits is 17496, while the sum is 41.

The square root of 11381999 is about 3373.7218320425. The cubic root of 11381999 is about 224.9431889490.

The spelling of 11381999 in words is "eleven million, three hundred eighty-one thousand, nine hundred ninety-nine".