405809809 has 16 divisors (see below), whose sum is σ = 442990080. Its totient is φ = 370327680.

The previous prime is 405809773. The next prime is 405809843. The reversal of 405809809 is 908908504.

It is a happy number.

It is a cyclic number.

It is not a de Polignac number, because 405809809 - 2⁷ = 405809681 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (405809849) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 135759 + ... + 138715.

It is an arithmetic number, because the mean of its divisors is an integer number (27686880).

Almost surely, 2^405809809 is an apocalyptic number.

It is an amenable number.

405809809 is a deficient number, since it is larger than the sum of its proper divisors (37180271).

405809809 is a wasteful number, since it uses less digits than its factorization.

405809809 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3240.

The product of its (nonzero) digits is 103680, while the sum is 43.

The square root of 405809809 is about 20144.7216163441. The cubic root of 405809809 is about 740.3564200976.

The spelling of 405809809 in words is "four hundred five million, eight hundred nine thousand, eight hundred nine".