405940 has 12 divisors (see below), whose sum is σ = 852516. Its totient is φ = 162368.

The previous prime is 405917. The next prime is 405947. The reversal of 405940 is 49504.

405940 = T₁₂₂ + T₁₂₃ + ... + T₁₆₁.

It can be written as a sum of positive squares in 2 ways, for example, as 169744 + 236196 = 412^2 + 486^2 .

It is an Ulam number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (405947) 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, 10129 + ... + 10168.

It is an arithmetic number, because the mean of its divisors is an integer number (71043).

2⁴⁰⁵⁹⁴⁰ is an apocalyptic number.

It is an amenable number.

405940 is an abundant number, since it is smaller than the sum of its proper divisors (446576).

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

405940 is a wasteful number, since it uses less digits than its factorization.

405940 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 20306 (or 20304 counting only the distinct ones).

The product of its (nonzero) digits is 720, while the sum is 22.

The square root of 405940 is about 637.1342087818. The cubic root of 405940 is about 74.0435584799.

The spelling of 405940 in words is "four hundred five thousand, nine hundred forty".