381565 has 12 divisors (see below), whose sum is σ = 492156. Its totient is φ = 283008.

The previous prime is 381559. The next prime is 381569. The reversal of 381565 is 565183.

It can be written as a sum of positive squares in 2 ways, for example, as 219961 + 161604 = 469^2 + 402^2 .

It is not a de Polignac number, because 381565 - 2⁵ = 381533 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (381569) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 5662 + ... + 5728.

It is an arithmetic number, because the mean of its divisors is an integer number (41013).

2³⁸¹⁵⁶⁵ is an apocalyptic number.

It is an amenable number.

381565 is a deficient number, since it is larger than the sum of its proper divisors (110591).

381565 is an equidigital number, since it uses as much as digits as its factorization.

381565 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 156 (or 89 counting only the distinct ones).

The product of its digits is 3600, while the sum is 28.

The square root of 381565 is about 617.7094786386. The cubic root of 381565 is about 72.5308628014.

It can be divided in two parts, 381 and 565, that added together give a triangular number (946 = T₄₃).

The spelling of 381565 in words is "three hundred eighty-one thousand, five hundred sixty-five".