521789 has 2 divisors, whose sum is σ = 521790. Its totient is φ = 521788.

The previous prime is 521777. The next prime is 521791. The reversal of 521789 is 987125.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 504100 + 17689 = 710^2 + 133^2 .

It is a cyclic number.

It is not a de Polignac number, because 521789 - 2⁸ = 521533 is a prime.

Together with 521791, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (521749) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 260894 + 260895.

It is an arithmetic number, because the mean of its divisors is an integer number (260895).

2⁵²¹⁷⁸⁹ is an apocalyptic number.

It is an amenable number.

521789 is a deficient number, since it is larger than the sum of its proper divisors (1).

521789 is an equidigital number, since it uses as much as digits as its factorization.

521789 is an evil number, because the sum of its binary digits is even.

The product of its digits is 5040, while the sum is 32.

The square root of 521789 is about 722.3496383331. The cubic root of 521789 is about 80.5066285708.

The spelling of 521789 in words is "five hundred twenty-one thousand, seven hundred eighty-nine".