381931 has 4 divisors (see below), whose sum is σ = 416664. Its totient is φ = 347200.

The previous prime is 381917. The next prime is 381937. The reversal of 381931 is 139183.

381931 = T₂₅₈ + T₂₅₉ + ... + T₂₆₈.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 139183 = 11 ⋅12653.

It is a cyclic number.

It is not a de Polignac number, because 381931 - 2⁹ = 381419 is a prime.

It is a super-3 number, since 3×381931³ = 167138301563332473, which contains 333 as substring. Note that it is a super-d number also for d = 2.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 381896 and 381905.

It is not an unprimeable number, because it can be changed into a prime (381937) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 17350 + ... + 17371.

It is an arithmetic number, because the mean of its divisors is an integer number (104166).

2³⁸¹⁹³¹ is an apocalyptic number.

381931 is a deficient number, since it is larger than the sum of its proper divisors (34733).

381931 is a wasteful number, since it uses less digits than its factorization.

381931 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 34732.

The product of its digits is 648, while the sum is 25.

The square root of 381931 is about 618.0056634045. The cubic root of 381931 is about 72.5540461057.

The spelling of 381931 in words is "three hundred eighty-one thousand, nine hundred thirty-one".