400665 has 8 divisors (see below), whose sum is σ = 641088. Its totient is φ = 213680.

The previous prime is 400657. The next prime is 400679. The reversal of 400665 is 566004.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 400665 - 2³ = 400657 is a prime.

It is an Ulam number.

It is a Curzon number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 400665.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 13341 + ... + 13370.

It is an arithmetic number, because the mean of its divisors is an integer number (80136).

2⁴⁰⁰⁶⁶⁵ is an apocalyptic number.

It is an amenable number.

400665 is a deficient number, since it is larger than the sum of its proper divisors (240423).

400665 is a wasteful number, since it uses less digits than its factorization.

400665 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 26719.

The product of its (nonzero) digits is 720, while the sum is 21.

The square root of 400665 is about 632.9810423701. The cubic root of 400665 is about 73.7214387154.

Adding to 400665 its reverse (566004), we get a palindrome (966669).

The spelling of 400665 in words is "four hundred thousand, six hundred sixty-five".