521881 has 2 divisors, whose sum is σ = 521882. Its totient is φ = 521880.

The previous prime is 521879. The next prime is 521887. The reversal of 521881 is 188125.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 518400 + 3481 = 720^2 + 59^2 .

It is a cyclic number.

It is not a de Polignac number, because 521881 - 2¹ = 521879 is a prime.

It is a super-2 number, since 2×521881² = 544719556322, which contains 22 as substring.

Together with 521879, it forms a pair of twin primes.

521881 is a lucky number.

It is not a weakly prime, because it can be changed into another prime (521887) 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 as a sum of consecutive naturals, namely, 260940 + 260941.

It is an arithmetic number, because the mean of its divisors is an integer number (260941).

2⁵²¹⁸⁸¹ is an apocalyptic number.

It is an amenable number.

521881 is a deficient number, since it is larger than the sum of its proper divisors (1).

521881 is an equidigital number, since it uses as much as digits as its factorization.

521881 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 640, while the sum is 25.

The square root of 521881 is about 722.4133165993. The cubic root of 521881 is about 80.5113598413.

The spelling of 521881 in words is "five hundred twenty-one thousand, eight hundred eighty-one".