521387 has 4 divisors (see below), whose sum is σ = 544080. Its totient is φ = 498696.

The previous prime is 521377. The next prime is 521393. The reversal of 521387 is 783125.

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

It is a cyclic number.

It is not a de Polignac number, because 521387 - 2¹⁰ = 520363 is a prime.

It is a Duffinian number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 521387.

It is not an unprimeable number, because it can be changed into a prime (521317) 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 3 ways as a sum of consecutive naturals, for example, 11312 + ... + 11357.

It is an arithmetic number, because the mean of its divisors is an integer number (136020).

2⁵²¹³⁸⁷ is an apocalyptic number.

521387 is a deficient number, since it is larger than the sum of its proper divisors (22693).

521387 is a wasteful number, since it uses less digits than its factorization.

521387 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 22692.

The product of its digits is 1680, while the sum is 26.

The square root of 521387 is about 722.0713261167. The cubic root of 521387 is about 80.4859484495.

The spelling of 521387 in words is "five hundred twenty-one thousand, three hundred eighty-seven".