400813 has 4 divisors (see below), whose sum is σ = 458080. Its totient is φ = 343548.

The previous prime is 400759. The next prime is 400823. The reversal of 400813 is 318004.

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 400813 - 2¹⁷ = 269741 is a prime.

400813 is a modest number, since divided by 813 gives 4 as remainder.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (400823) 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 3 ways as a sum of consecutive naturals, for example, 28623 + ... + 28636.

It is an arithmetic number, because the mean of its divisors is an integer number (114520).

2⁴⁰⁰⁸¹³ is an apocalyptic number.

It is an amenable number.

400813 is a deficient number, since it is larger than the sum of its proper divisors (57267).

400813 is an equidigital number, since it uses as much as digits as its factorization.

400813 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 57266.

The product of its (nonzero) digits is 96, while the sum is 16.

The square root of 400813 is about 633.0979387109. The cubic root of 400813 is about 73.7305148179.

Adding to 400813 its reverse (318004), we get a palindrome (718817).

The spelling of 400813 in words is "four hundred thousand, eight hundred thirteen".