405561 has 8 divisors (see below), whose sum is σ = 582400. Its totient is φ = 249552.

The previous prime is 405553. The next prime is 405577. The reversal of 405561 is 165504.

It is a happy number.

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

It is not a de Polignac number, because 405561 - 2³ = 405553 is a prime.

It is a Curzon number.

405561 is a lucky number.

It is not an unprimeable number, because it can be changed into a prime (405521) 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, 5161 + ... + 5238.

It is an arithmetic number, because the mean of its divisors is an integer number (72800).

2⁴⁰⁵⁵⁶¹ is an apocalyptic number.

It is an amenable number.

405561 is a deficient number, since it is larger than the sum of its proper divisors (176839).

405561 is a wasteful number, since it uses less digits than its factorization.

405561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10415.

The product of its (nonzero) digits is 600, while the sum is 21.

The square root of 405561 is about 636.8367137658. The cubic root of 405561 is about 74.0205080729.

The spelling of 405561 in words is "four hundred five thousand, five hundred sixty-one".