405647 has 4 divisors (see below), whose sum is σ = 442536. Its totient is φ = 368760.

The previous prime is 405641. The next prime is 405659. The reversal of 405647 is 746504.

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

It is a cyclic number.

It is not a de Polignac number, because 405647 - 2¹² = 401551 is a prime.

It is a Duffinian number.

It is a congruent number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 405647.

It is not an unprimeable number, because it can be changed into a prime (405641) 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, 18428 + ... + 18449.

It is an arithmetic number, because the mean of its divisors is an integer number (110634).

2⁴⁰⁵⁶⁴⁷ is an apocalyptic number.

405647 is a deficient number, since it is larger than the sum of its proper divisors (36889).

405647 is a wasteful number, since it uses less digits than its factorization.

405647 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 36888.

The product of its (nonzero) digits is 3360, while the sum is 26.

The square root of 405647 is about 636.9042314194. The cubic root of 405647 is about 74.0257397675.

The spelling of 405647 in words is "four hundred five thousand, six hundred forty-seven".