378691

378691 is a natural number. It follows 378690 and precedes 378692. In mathematics, it is notable for being a prime number: its only positive divisors are 1 and itself. The number is odd and not divisible by 3 or 5, as indicated by the digit sum (3+7+8+6+9+1 = 34) and by its final digit 1. A comprehensive divisibility check against all primes up to 613 yields no divisors; since the square root of 378691 is about 615, this verifies primality.

From a modular arithmetic perspective, 378691 is congruent to 3 modulo 4, i.e., it cannot be expressed as a sum of two squares. This property is shared by primes that are congruent to 3 modulo 4.

Numerically, 378691 is a six-digit prime. It has not been highlighted in widely known mathematical constants or named sequences beyond its status as a prime. In practical terms, a six-digit prime like this is far too small to be used in modern cryptography, where keys typically operate on hundreds to thousands of bits.

As a plain integer, 378691 may appear in various numerical datasets, puzzles, or enumerations, but no widely recognized historical events or mathematical theorems are specifically tied to this exact value.