838405 has 8 divisors (see below), whose sum is σ = 1020312. Its totient is φ = 661248.

The previous prime is 838403. The next prime is 838421. The reversal of 838405 is 504838.

It can be written as a sum of positive squares in 4 ways, for example, as 93636 + 744769 = 306^2 + 863^2 .

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 838405 - 2¹ = 838403 is a prime.

It is a Duffinian number.

838405 is a lucky number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (838403) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 784 + ... + 1513.

It is an arithmetic number, because the mean of its divisors is an integer number (127539).

2⁸³⁸⁴⁰⁵ is an apocalyptic number.

It is an amenable number.

838405 is a deficient number, since it is larger than the sum of its proper divisors (181907).

838405 is a wasteful number, since it uses less digits than its factorization.

838405 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2375.

The product of its (nonzero) digits is 3840, while the sum is 28.

The square root of 838405 is about 915.6445817019. The cubic root of 838405 is about 94.2941217524.

It can be divided in two parts, 83840 and 5, that added together give a triangular number (83845 = T₄₀₉).

The spelling of 838405 in words is "eight hundred thirty-eight thousand, four hundred five".