400909 has 4 divisors (see below), whose sum is σ = 403200. Its totient is φ = 398620.

The previous prime is 400903. The next prime is 400927. The reversal of 400909 is 909004.

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 a cyclic number.

It is not a de Polignac number, because 400909 - 2¹⁵ = 368141 is a prime.

It is a Duffinian number.

400909 is a modest number, since divided by 909 gives 40 as remainder.

It is a self number, because there is not a number n which added to its sum of digits gives 400909.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (400903) 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, 859 + ... + 1240.

It is an arithmetic number, because the mean of its divisors is an integer number (100800).

2⁴⁰⁰⁹⁰⁹ is an apocalyptic number.

It is an amenable number.

400909 is a deficient number, since it is larger than the sum of its proper divisors (2291).

400909 is a wasteful number, since it uses less digits than its factorization.

400909 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2290.

The product of its (nonzero) digits is 324, while the sum is 22.

The square root of 400909 is about 633.1737518249. The cubic root of 400909 is about 73.7364008249.

The spelling of 400909 in words is "four hundred thousand, nine hundred nine".