400865 has 4 divisors (see below), whose sum is σ = 481044. Its totient is φ = 320688.

The previous prime is 400859. The next prime is 400871. The reversal of 400865 is 568004.

It is a semiprime because it is the product of two primes.

It is an interprime number because it is at equal distance from previous prime (400859) and next prime (400871).

It can be written as a sum of positive squares in 2 ways, for example, as 113569 + 287296 = 337^2 + 536^2 .

It is a cyclic number.

It is not a de Polignac number, because 400865 - 2⁴ = 400849 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 400865.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 40082 + ... + 40091.

It is an arithmetic number, because the mean of its divisors is an integer number (120261).

2⁴⁰⁰⁸⁶⁵ is an apocalyptic number.

It is an amenable number.

400865 is a deficient number, since it is larger than the sum of its proper divisors (80179).

400865 is an equidigital number, since it uses as much as digits as its factorization.

400865 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 80178.

The product of its (nonzero) digits is 960, while the sum is 23.

The square root of 400865 is about 633.1390052745. The cubic root of 400865 is about 73.7337031883.

Adding to 400865 its reverse (568004), we get a palindrome (968869).

The spelling of 400865 in words is "four hundred thousand, eight hundred sixty-five".