400531 has 4 divisors (see below), whose sum is σ = 402192. Its totient is φ = 398872.

The previous prime is 400523. The next prime is 400559. The reversal of 400531 is 135004.

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

It is a cyclic number.

It is not a de Polignac number, because 400531 - 2³ = 400523 is a prime.

It is a super-2 number, since 2×400531² = 320850163922, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (400031) 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, 391 + ... + 976.

It is an arithmetic number, because the mean of its divisors is an integer number (100548).

2⁴⁰⁰⁵³¹ is an apocalyptic number.

400531 is a deficient number, since it is larger than the sum of its proper divisors (1661).

400531 is a wasteful number, since it uses less digits than its factorization.

400531 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1660.

The product of its (nonzero) digits is 60, while the sum is 13.

The square root of 400531 is about 632.8751851669. The cubic root of 400531 is about 73.7132192351.

Adding to 400531 its reverse (135004), we get a palindrome (535535).

The spelling of 400531 in words is "four hundred thousand, five hundred thirty-one".