521720 has 16 divisors (see below), whose sum is σ = 1173960. Its totient is φ = 208672.

The previous prime is 521707. The next prime is 521723. The reversal of 521720 is 27125.

It is a zygodrome in base 3.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (521723) 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, 6482 + ... + 6561.

2⁵²¹⁷²⁰ is an apocalyptic number.

It is an amenable number.

521720 is an abundant number, since it is smaller than the sum of its proper divisors (652240).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

521720 is a wasteful number, since it uses less digits than its factorization.

521720 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 13054 (or 13050 counting only the distinct ones).

The product of its (nonzero) digits is 140, while the sum is 17.

The square root of 521720 is about 722.3018759494. The cubic root of 521720 is about 80.5030797531.

Adding to 521720 its reverse (27125), we get a palindrome (548845).

The spelling of 521720 in words is "five hundred twenty-one thousand, seven hundred twenty".