381643 has 4 divisors (see below), whose sum is σ = 383128. Its totient is φ = 380160.

The previous prime is 381637. The next prime is 381659. The reversal of 381643 is 346183.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 346183 = 103 ⋅3361.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-381643 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (381673) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 246 + ... + 907.

It is an arithmetic number, because the mean of its divisors is an integer number (95782).

2³⁸¹⁶⁴³ is an apocalyptic number.

381643 is a deficient number, since it is larger than the sum of its proper divisors (1485).

381643 is a wasteful number, since it uses less digits than its factorization.

381643 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1484.

The product of its digits is 1728, while the sum is 25.

The square root of 381643 is about 617.7726118889. The cubic root of 381643 is about 72.5358047482.

It can be divided in two parts, 381 and 643, that added together give a 10-th power (1024 = 2¹⁰).

The spelling of 381643 in words is "three hundred eighty-one thousand, six hundred forty-three".