381649 has 4 divisors (see below), whose sum is σ = 386560. Its totient is φ = 376740.

The previous prime is 381637. The next prime is 381659. The reversal of 381649 is 946183.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-381649 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 381649.

It is not an unprimeable number, because it can be changed into a prime (381629) 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, 2337 + ... + 2494.

It is an arithmetic number, because the mean of its divisors is an integer number (96640).

2³⁸¹⁶⁴⁹ is an apocalyptic number.

It is an amenable number.

381649 is a deficient number, since it is larger than the sum of its proper divisors (4911).

381649 is an equidigital number, since it uses as much as digits as its factorization.

381649 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4910.

The product of its digits is 5184, while the sum is 31.

The square root of 381649 is about 617.7774680255. Note that the first 3 decimals coincide. The cubic root of 381649 is about 72.5361848701.

The spelling of 381649 in words is "three hundred eighty-one thousand, six hundred forty-nine".