66405 has 16 divisors (see below), whose sum is σ = 112320. Its totient is φ = 33408.

The previous prime is 66403. The next prime is 66413. The reversal of 66405 is 50466.

It is not a de Polignac number, because 66405 - 2¹ = 66403 is a prime.

It is a nialpdrome in base 5.

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 66405.

It is not an unprimeable number, because it can be changed into a prime (66403) by changing a digit.

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 15 ways as a sum of consecutive naturals, for example, 169 + ... + 401.

It is an arithmetic number, because the mean of its divisors is an integer number (7020).

2⁶⁶⁴⁰⁵ is an apocalyptic number.

It is an amenable number.

66405 is a deficient number, since it is larger than the sum of its proper divisors (45915).

66405 is a wasteful number, since it uses less digits than its factorization.

66405 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 260.

The product of its (nonzero) digits is 720, while the sum is 21.

The square root of 66405 is about 257.6916762334. The cubic root of 66405 is about 40.4948934272.

The spelling of 66405 in words is "sixty-six thousand, four hundred five".