381665 has 4 divisors (see below), whose sum is σ = 458004. Its totient is φ = 305328.

The previous prime is 381659. The next prime is 381673. The reversal of 381665 is 566183.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 110224 + 271441 = 332^2 + 521^2 .

It is a cyclic number.

It is not a de Polignac number, because 381665 - 2¹⁰ = 380641 is a prime.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 38162 + ... + 38171.

It is an arithmetic number, because the mean of its divisors is an integer number (114501).

2³⁸¹⁶⁶⁵ is an apocalyptic number.

It is an amenable number.

381665 is a deficient number, since it is larger than the sum of its proper divisors (76339).

381665 is an equidigital number, since it uses as much as digits as its factorization.

381665 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 76338.

The product of its digits is 4320, while the sum is 29.

The square root of 381665 is about 617.7904175366. The cubic root of 381665 is about 72.5371985089.

The spelling of 381665 in words is "three hundred eighty-one thousand, six hundred sixty-five".