521609 has 4 divisors (see below), whose sum is σ = 569040. Its totient is φ = 474180.

The previous prime is 521603. The next prime is 521641. The reversal of 521609 is 906125.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 521609 - 2¹² = 517513 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (521603) 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, 23699 + ... + 23720.

It is an arithmetic number, because the mean of its divisors is an integer number (142260).

2⁵²¹⁶⁰⁹ is an apocalyptic number.

It is an amenable number.

521609 is a deficient number, since it is larger than the sum of its proper divisors (47431).

521609 is a wasteful number, since it uses less digits than its factorization.

521609 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 47430.

The product of its (nonzero) digits is 540, while the sum is 23.

The square root of 521609 is about 722.2250341826. The cubic root of 521609 is about 80.4973701287.

It can be divided in two parts, 52 and 1609, that added together give a palindrome (1661).

The spelling of 521609 in words is "five hundred twenty-one thousand, six hundred nine".