381818 has 4 divisors (see below), whose sum is σ = 572730. Its totient is φ = 190908.

The previous prime is 381817. The next prime is 381841. The reversal of 381818 is 818183.

It is a happy number.

381818 is digitally balanced in base 3, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 818183 = 31 ⋅26393.

It can be written as a sum of positive squares in only one way, i.e., 344569 + 37249 = 587^2 + 193^2 .

It is an alternating number because its digits alternate between odd and even.

381818 is a modest number, since divided by 1818 gives 38 as remainder.

It is not an unprimeable number, because it can be changed into a prime (381817) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 95453 + ... + 95456.

2³⁸¹⁸¹⁸ is an apocalyptic number.

381818 is a deficient number, since it is larger than the sum of its proper divisors (190912).

381818 is a wasteful number, since it uses less digits than its factorization.

381818 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 190911.

The product of its digits is 1536, while the sum is 29.

The square root of 381818 is about 617.9142335308. The cubic root of 381818 is about 72.5468899999.

The spelling of 381818 in words is "three hundred eighty-one thousand, eight hundred eighteen".