381666 has 8 divisors (see below), whose sum is σ = 763344. Its totient is φ = 127220.

The previous prime is 381659. The next prime is 381673. The reversal of 381666 is 666183.

It is an interprime number because it is at equal distance from previous prime (381659) and next prime (381673).

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

381666 is an admirable number.

It is an unprimeable number.

381666 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 31800 + ... + 31811.

It is an arithmetic number, because the mean of its divisors is an integer number (95418).

2³⁸¹⁶⁶⁶ is an apocalyptic number.

381666 is a primitive abundant number, since it is smaller than the sum of its proper divisors, none of which is abundant.

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

381666 is a wasteful number, since it uses less digits than its factorization.

381666 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 63616.

The product of its digits is 5184, while the sum is 30.

The square root of 381666 is about 617.7912268720. The cubic root of 381666 is about 72.5372618604.

The spelling of 381666 in words is "three hundred eighty-one thousand, six hundred sixty-six".