405655 has 4 divisors (see below), whose sum is σ = 486792. Its totient is φ = 324520.

The previous prime is 405641. The next prime is 405659. The reversal of 405655 is 556504.

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

It is not a de Polignac number, because 405655 - 2⁷ = 405527 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (405659) 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, 40561 + ... + 40570.

It is an arithmetic number, because the mean of its divisors is an integer number (121698).

2⁴⁰⁵⁶⁵⁵ is an apocalyptic number.

405655 is a deficient number, since it is larger than the sum of its proper divisors (81137).

405655 is an equidigital number, since it uses as much as digits as its factorization.

405655 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 81136.

The product of its (nonzero) digits is 3000, while the sum is 25.

The square root of 405655 is about 636.9105117675. The cubic root of 405655 is about 74.0262263991.

The spelling of 405655 in words is "four hundred five thousand, six hundred fifty-five".