381491881 has 4 divisors (see below), whose sum is σ = 381589972. Its totient is φ = 381393792.

The previous prime is 381491863. The next prime is 381491909. The reversal of 381491881 is 188194183.

It is a happy number.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 205664281 + 175827600 = 14341^2 + 13260^2 .

It is a cyclic number.

It is not a de Polignac number, because 381491881 - 2¹¹ = 381489833 is a prime.

It is a super-2 number, since 2×381491881² = 291072110537836322, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (381491281) 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, 42960 + ... + 51073.

It is an arithmetic number, because the mean of its divisors is an integer number (95397493).

Almost surely, 2^381491881 is an apocalyptic number.

It is an amenable number.

381491881 is a deficient number, since it is larger than the sum of its proper divisors (98091).

381491881 is an equidigital number, since it uses as much as digits as its factorization.

381491881 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 98090.

The product of its digits is 55296, while the sum is 43.

The square root of 381491881 is about 19531.8171453657. The cubic root of 381491881 is about 725.2622949472.

The spelling of 381491881 in words is "three hundred eighty-one million, four hundred ninety-one thousand, eight hundred eighty-one".