381440 has 40 divisors (see below), whose sum is σ = 920700. Its totient is φ = 151552.

The previous prime is 381439. The next prime is 381443. The reversal of 381440 is 44183.

It can be written as a sum of positive squares in 2 ways, for example, as 350464 + 30976 = 592^2 + 176^2 .

It is a tau number, because it is divible by the number of its divisors (40).

It is a Harshad number since it is a multiple of its sum of digits (20).

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 381440.

It is not an unprimeable number, because it can be changed into a prime (381443) 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, 2486 + ... + 2634.

2³⁸¹⁴⁴⁰ is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 381440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (460350).

381440 is an abundant number, since it is smaller than the sum of its proper divisors (539260).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

381440 is an equidigital number, since it uses as much as digits as its factorization.

381440 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 172 (or 156 counting only the distinct ones).

The product of its (nonzero) digits is 384, while the sum is 20.

The square root of 381440 is about 617.6082900998. The cubic root of 381440 is about 72.5229416101.

The spelling of 381440 in words is "three hundred eighty-one thousand, four hundred forty".