406521 has 12 divisors (see below), whose sum is σ = 621972. Its totient is φ = 254976.

The previous prime is 406517. The next prime is 406531. The reversal of 406521 is 125604.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 291600 + 114921 = 540^2 + 339^2 .

It is not a de Polignac number, because 406521 - 2² = 406517 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 406494 and 406503.

It is not an unprimeable number, because it can be changed into a prime (406501) 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, 1176 + ... + 1481.

It is an arithmetic number, because the mean of its divisors is an integer number (51831).

2⁴⁰⁶⁵²¹ is an apocalyptic number.

It is an amenable number.

406521 is a deficient number, since it is larger than the sum of its proper divisors (215451).

406521 is a wasteful number, since it uses less digits than its factorization.

406521 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2680 (or 2677 counting only the distinct ones).

The product of its (nonzero) digits is 240, while the sum is 18.

The square root of 406521 is about 637.5899936480. The cubic root of 406521 is about 74.0788664893.

It can be divided in two parts, 40 and 6521, that added together give a 8-th power (6561 = 3⁸).

The spelling of 406521 in words is "four hundred six thousand, five hundred twenty-one".