400521 has 16 divisors (see below), whose sum is σ = 596160. Its totient is φ = 237120.

The previous prime is 400481. The next prime is 400523. The reversal of 400521 is 125004.

It is not a de Polignac number, because 400521 - 2⁶ = 400457 is a prime.

400521 is a lucky number.

It is a junction number, because it is equal to n+sod(n) for n = 400497 and 400506.

It is not an unprimeable number, because it can be changed into a prime (400523) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1635 + ... + 1863.

It is an arithmetic number, because the mean of its divisors is an integer number (37260).

2⁴⁰⁰⁵²¹ is an apocalyptic number.

It is an amenable number.

400521 is a deficient number, since it is larger than the sum of its proper divisors (195639).

400521 is a wasteful number, since it uses less digits than its factorization.

400521 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 296.

The product of its (nonzero) digits is 40, while the sum is 12.

The square root of 400521 is about 632.8672846656. The cubic root of 400521 is about 73.7126057675.

Adding to 400521 its reverse (125004), we get a palindrome (525525).

The spelling of 400521 in words is "four hundred thousand, five hundred twenty-one".