400385 has 4 divisors (see below), whose sum is σ = 480468. Its totient is φ = 320304.

The previous prime is 400381. The next prime is 400391. The reversal of 400385 is 583004.

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

It can be written as a sum of positive squares in 2 ways, for example, as 163216 + 237169 = 404^2 + 487^2 .

It is a cyclic number.

It is not a de Polignac number, because 400385 - 2² = 400381 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (400381) 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, 40034 + ... + 40043.

It is an arithmetic number, because the mean of its divisors is an integer number (120117).

It is a Proth number, since it is equal to 391 ⋅ 2¹⁰ + 1 and 391 < 2¹⁰.

2⁴⁰⁰³⁸⁵ is an apocalyptic number.

It is an amenable number.

400385 is a deficient number, since it is larger than the sum of its proper divisors (80083).

400385 is an equidigital number, since it uses as much as digits as its factorization.

400385 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 80082.

The product of its (nonzero) digits is 480, while the sum is 20.

The square root of 400385 is about 632.7598280548. The cubic root of 400385 is about 73.7042615947.

Adding to 400385 its reverse (583004), we get a palindrome (983389).

The spelling of 400385 in words is "four hundred thousand, three hundred eighty-five".