381561 has 8 divisors (see below), whose sum is σ = 512160. Its totient is φ = 252672.

The previous prime is 381559. The next prime is 381569. The reversal of 381561 is 165183.

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

It is not a de Polignac number, because 381561 - 2¹ = 381559 is a prime.

It is a Curzon number.

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

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 250 + ... + 908.

It is an arithmetic number, because the mean of its divisors is an integer number (64020).

2³⁸¹⁵⁶¹ is an apocalyptic number.

It is an amenable number.

381561 is a deficient number, since it is larger than the sum of its proper divisors (130599).

381561 is a wasteful number, since it uses less digits than its factorization.

381561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 855.

The product of its digits is 720, while the sum is 24.

The square root of 381561 is about 617.7062408621. The cubic root of 381561 is about 72.5306093500.

The spelling of 381561 in words is "three hundred eighty-one thousand, five hundred sixty-one".