309381 has 8 divisors (see below), whose sum is σ = 415104. Its totient is φ = 204960.

The previous prime is 309371. The next prime is 309391. The reversal of 309381 is 183903.

It is an interprime number because it is at equal distance from previous prime (309371) and next prime (309391).

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 309381 - 2⁶ = 309317 is a prime.

It is a super-2 number, since 2×309381² = 191433206322, which contains 22 as substring.

309381 is a lucky number.

It is a nialpdrome in base 13.

It is a congruent number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 309381.

It is not an unprimeable number, because it can be changed into a prime (309311) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 660 + ... + 1026.

It is an arithmetic number, because the mean of its divisors is an integer number (51888).

2³⁰⁹³⁸¹ is an apocalyptic number.

It is an amenable number.

309381 is a deficient number, since it is larger than the sum of its proper divisors (105723).

309381 is a wasteful number, since it uses less digits than its factorization.

309381 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 651.

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

The square root of 309381 is about 556.2202801049. The cubic root of 309381 is about 67.6339179486.

The spelling of 309381 in words is "three hundred nine thousand, three hundred eighty-one".