381309 has 4 divisors (see below), whose sum is σ = 508416. Its totient is φ = 254204.

The previous prime is 381301. The next prime is 381319. The reversal of 381309 is 903183.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 381309 - 2³ = 381301 is a prime.

It is a D-number.

381309 is a lucky number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (381301) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 63549 + ... + 63554.

It is an arithmetic number, because the mean of its divisors is an integer number (127104).

2³⁸¹³⁰⁹ is an apocalyptic number.

It is an amenable number.

381309 is a deficient number, since it is larger than the sum of its proper divisors (127107).

381309 is a wasteful number, since it uses less digits than its factorization.

381309 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 127106.

The product of its (nonzero) digits is 648, while the sum is 24.

The square root of 381309 is about 617.5022267166. The cubic root of 381309 is about 72.5146383442.

The spelling of 381309 in words is "three hundred eighty-one thousand, three hundred nine".