521989 has 4 divisors (see below), whose sum is σ = 562156. Its totient is φ = 481824.

The previous prime is 521981. The next prime is 521993. The reversal of 521989 is 989125.

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

It can be written as a sum of positive squares in 2 ways, for example, as 173889 + 348100 = 417^2 + 590^2 .

It is a cyclic number.

It is not a de Polignac number, because 521989 - 2³ = 521981 is a prime.

It is a super-2 number, since 2×521989² = 544945032242, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (521981) 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, 20064 + ... + 20089.

It is an arithmetic number, because the mean of its divisors is an integer number (140539).

2⁵²¹⁹⁸⁹ is an apocalyptic number.

It is an amenable number.

521989 is a deficient number, since it is larger than the sum of its proper divisors (40167).

521989 is a wasteful number, since it uses less digits than its factorization.

521989 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 40166.

The product of its digits is 6480, while the sum is 34.

The square root of 521989 is about 722.4880621851. The cubic root of 521989 is about 80.5169132319.

The spelling of 521989 in words is "five hundred twenty-one thousand, nine hundred eighty-nine".