400581 has 12 divisors (see below), whose sum is σ = 591552. Its totient is φ = 261096.

The previous prime is 400579. The next prime is 400597. The reversal of 400581 is 185004.

It is not a de Polignac number, because 400581 - 2¹ = 400579 is a prime.

It is a super-2 number, since 2×400581² = 320930275122, which contains 22 as substring.

It is a congruent number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 400581.

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 11 ways as a sum of consecutive naturals, for example, 51 + ... + 896.

It is an arithmetic number, because the mean of its divisors is an integer number (49296).

2⁴⁰⁰⁵⁸¹ is an apocalyptic number.

It is an amenable number.

400581 is a deficient number, since it is larger than the sum of its proper divisors (190971).

400581 is a wasteful number, since it uses less digits than its factorization.

400581 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1000 (or 997 counting only the distinct ones).

The product of its (nonzero) digits is 160, while the sum is 18.

The square root of 400581 is about 632.9146861940. The cubic root of 400581 is about 73.7162864197.

Adding to 400581 its reverse (185004), we get a palindrome (585585).

The spelling of 400581 in words is "four hundred thousand, five hundred eighty-one".