381990 has 64 divisors (see below), whose sum is σ = 1119744. Its totient is φ = 81408.

The previous prime is 381989. The next prime is 381991. The reversal of 381990 is 99183.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (381989) and next prime (381991).

It is a Harshad number since it is a multiple of its sum of digits (30).

It is a congruent number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 381990.

It is not an unprimeable number, because it can be changed into a prime (381991) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 3517 + ... + 3623.

It is an arithmetic number, because the mean of its divisors is an integer number (17496).

2³⁸¹⁹⁹⁰ is an apocalyptic number.

381990 is a gapful number since it is divisible by the number (30) formed by its first and last digit.

It is a practical number, because each smaller number is the sum of distinct divisors of 381990, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (559872).

381990 is an abundant number, since it is smaller than the sum of its proper divisors (737754).

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

381990 is a wasteful number, since it uses less digits than its factorization.

381990 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 141.

The product of its (nonzero) digits is 1944, while the sum is 30.

The square root of 381990 is about 618.0533957515. The cubic root of 381990 is about 72.5577819186.

The spelling of 381990 in words is "three hundred eighty-one thousand, nine hundred ninety".