405680 has 40 divisors (see below), whose sum is σ = 1031184. Its totient is φ = 147200.

The previous prime is 405679. The next prime is 405683. The reversal of 405680 is 86504.

It is a tau number, because it is divible by the number of its divisors (40).

It is not an unprimeable number, because it can be changed into a prime (405683) 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 7 ways as a sum of consecutive naturals, for example, 650 + ... + 1110.

2⁴⁰⁵⁶⁸⁰ is an apocalyptic number.

405680 is a gapful number since it is divisible by the number (40) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 405680, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (515592).

405680 is an abundant number, since it is smaller than the sum of its proper divisors (625504).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

405680 is a wasteful number, since it uses less digits than its factorization.

405680 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 485 (or 479 counting only the distinct ones).

The product of its (nonzero) digits is 960, while the sum is 23.

The square root of 405680 is about 636.9301374562. The cubic root of 405680 is about 74.0277470819.

The spelling of 405680 in words is "four hundred five thousand, six hundred eighty".