405890 has 16 divisors (see below), whose sum is σ = 751032. Its totient is φ = 157824.

The previous prime is 405871. The next prime is 405893. The reversal of 405890 is 98504.

It can be written as a sum of positive squares in 4 ways, for example, as 358801 + 47089 = 599^2 + 217^2 .

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (405893) 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, 179 + ... + 918.

2⁴⁰⁵⁸⁹⁰ is an apocalyptic number.

405890 is a deficient number, since it is larger than the sum of its proper divisors (345142).

405890 is a wasteful number, since it uses less digits than its factorization.

405890 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1141.

The product of its (nonzero) digits is 1440, while the sum is 26.

The square root of 405890 is about 637.0949693727. The cubic root of 405890 is about 74.0405183509.

The spelling of 405890 in words is "four hundred five thousand, eight hundred ninety".