405638 has 8 divisors (see below), whose sum is σ = 613632. Its totient is φ = 201096.

The previous prime is 405611. The next prime is 405641. The reversal of 405638 is 836504.

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

It is a Curzon number.

It is a congruent number.

It is an unprimeable number.

405638 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 545 + ... + 1052.

It is an arithmetic number, because the mean of its divisors is an integer number (76704).

2⁴⁰⁵⁶³⁸ is an apocalyptic number.

405638 is a deficient number, since it is larger than the sum of its proper divisors (207994).

405638 is a wasteful number, since it uses less digits than its factorization.

405638 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1726.

The product of its (nonzero) digits is 2880, while the sum is 26.

The square root of 405638 is about 636.8971659538. The cubic root of 405638 is about 74.0251922992.

The spelling of 405638 in words is "four hundred five thousand, six hundred thirty-eight".