400008909 has 4 divisors (see below), whose sum is σ = 533345216. Its totient is φ = 266672604.

The previous prime is 400008899. The next prime is 400008937. The reversal of 400008909 is 909800004.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is not a de Polignac number, because 400008909 - 2²⁵ = 366454477 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (400008949) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 66668149 + ... + 66668154.

It is an arithmetic number, because the mean of its divisors is an integer number (133336304).

Almost surely, 2^400008909 is an apocalyptic number.

It is an amenable number.

400008909 is a deficient number, since it is larger than the sum of its proper divisors (133336307).

400008909 is a wasteful number, since it uses less digits than its factorization.

400008909 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 133336306.

The product of its (nonzero) digits is 2592, while the sum is 30.

The square root of 400008909 is about 20000.2227237599. Note that the first 3 decimals coincide. The cubic root of 400008909 is about 736.8117698602.

The spelling of 400008909 in words is "four hundred million, eight thousand, nine hundred nine".