521667 has 12 divisors (see below), whose sum is σ = 778440. Its totient is φ = 345276.

The previous prime is 521659. The next prime is 521669. The reversal of 521667 is 766125.

It is a powerful number, because all its prime factors have an exponent greater than 1 and also an Achilles number because it is not a perfect power.

It is not a de Polignac number, because 521667 - 2³ = 521659 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a self number, because there is not a number n which added to its sum of digits gives 521667.

It is not an unprimeable number, because it can be changed into a prime (521669) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 3684 + ... + 3822.

It is an arithmetic number, because the mean of its divisors is an integer number (64870).

2⁵²¹⁶⁶⁷ is an apocalyptic number.

521667 is a deficient number, since it is larger than the sum of its proper divisors (256773).

521667 is an equidigital number, since it uses as much as digits as its factorization.

521667 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 287 (or 142 counting only the distinct ones).

The product of its digits is 2520, while the sum is 27.

The square root of 521667 is about 722.2651867562. The cubic root of 521667 is about 80.5003536371.

Multiplying 521667 by its sum of digits (27), we get a square (14085009 = 3753²).

521667 divided by its sum of digits (27) gives a square (19321 = 139²).

The spelling of 521667 in words is "five hundred twenty-one thousand, six hundred sixty-seven".