408781 has 4 divisors (see below), whose sum is σ = 410332. Its totient is φ = 407232.

The previous prime is 408773. The next prime is 408787. The reversal of 408781 is 187804.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 54756 + 354025 = 234^2 + 595^2 .

It is a cyclic number.

It is not a de Polignac number, because 408781 - 2³ = 408773 is a prime.

It is a super-2 number, since 2×408781² = 334203811922, which contains 22 as substring.

It is a Duffinian number.

408781 is a lucky number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (408787) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 270 + ... + 943.

It is an arithmetic number, because the mean of its divisors is an integer number (102583).

2⁴⁰⁸⁷⁸¹ is an apocalyptic number.

It is an amenable number.

408781 is a deficient number, since it is larger than the sum of its proper divisors (1551).

408781 is a wasteful number, since it uses less digits than its factorization.

408781 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1550.

The product of its (nonzero) digits is 1792, while the sum is 28.

The square root of 408781 is about 639.3598360861. The cubic root of 408781 is about 74.2158901169.

The spelling of 408781 in words is "four hundred eight thousand, seven hundred eighty-one".