400309 has 16 divisors (see below), whose sum is σ = 508032. Its totient is φ = 307008.

The previous prime is 400307. The next prime is 400313. The reversal of 400309 is 903004.

It is not a de Polignac number, because 400309 - 2¹ = 400307 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 400292 and 400301.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (400307) 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 15 ways as a sum of consecutive naturals, for example, 4782 + ... + 4864.

It is an arithmetic number, because the mean of its divisors is an integer number (31752).

2⁴⁰⁰³⁰⁹ is an apocalyptic number.

It is an amenable number.

400309 is a deficient number, since it is larger than the sum of its proper divisors (107723).

400309 is a wasteful number, since it uses less digits than its factorization.

400309 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 156.

The product of its (nonzero) digits is 108, while the sum is 16.

The square root of 400309 is about 632.6997708234. The cubic root of 400309 is about 73.6995978516.

The spelling of 400309 in words is "four hundred thousand, three hundred nine".