5381

5381 is a natural number that comes after 5380 and before 5382. In mathematics, 5381 is a prime number, meaning it has no positive divisors other than 1 and itself. It is odd and not divisible by 2, 3, or 5, and its square root is approximately 73.3, so primality can be checked by testing divisors up to 73.

As a prime, 5381 is also congruent to 1 modulo 4, which implies, by a classical result in number theory, that it can be expressed as the sum of two squares. This property places 5381 among primes that can be written in the form a^2 + b^2 for integers a and b.

5381 Sekanina refers to a main-belt asteroid designated with the number 5381. The asteroid is named in honor of the Czech astronomer Zdeněk Sekanina, who is known for his work on comets and planetary science. As a minor planet, 5381 Sekanina is part of the catalog of objects orbiting the Sun between Mars and Jupiter.

In sum, 5381 is primarily recognized as a prime number with the usual arithmetic properties associated with primes, and it also appears in astronomy as the name of a main-belt asteroid.