381643921 has 8 divisors (see below), whose sum is σ = 384980904. Its totient is φ = 378318720.

The previous prime is 381643909. The next prime is 381643939. The reversal of 381643921 is 129346183.

It can be written as a sum of positive squares in 4 ways, for example, as 13771521 + 367872400 = 3711^2 + 19180^2 .

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

It is a cyclic number.

It is not a de Polignac number, because 381643921 - 2⁷ = 381643793 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (381643321) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 69741 + ... + 75013.

It is an arithmetic number, because the mean of its divisors is an integer number (48122613).

Almost surely, 2^381643921 is an apocalyptic number.

It is an amenable number.

381643921 is a deficient number, since it is larger than the sum of its proper divisors (3336983).

381643921 is a wasteful number, since it uses less digits than its factorization.

381643921 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5891.

The product of its digits is 31104, while the sum is 37.

The square root of 381643921 is about 19535.7088686334. The cubic root of 381643921 is about 725.3586309718.

The spelling of 381643921 in words is "three hundred eighty-one million, six hundred forty-three thousand, nine hundred twenty-one".