381191999 has 4 divisors (see below), whose sum is σ = 381233664. Its totient is φ = 381150336.

The previous prime is 381191977. The next prime is 381192017. The reversal of 381191999 is 999191183.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It is a cyclic number.

It is not a de Polignac number, because 381191999 - 2²⁸ = 112756543 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 (381191929) 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, 482 + ... + 27615.

It is an arithmetic number, because the mean of its divisors is an integer number (95308416).

Almost surely, 2^381191999 is an apocalyptic number.

381191999 is a deficient number, since it is larger than the sum of its proper divisors (41665).

381191999 is a wasteful number, since it uses less digits than its factorization.

381191999 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 41664.

The product of its digits is 157464, while the sum is 50.

The square root of 381191999 is about 19524.1388798584. The cubic root of 381191999 is about 725.0722077902.

The spelling of 381191999 in words is "three hundred eighty-one million, one hundred ninety-one thousand, nine hundred ninety-nine".