521791 has 2 divisors, whose sum is σ = 521792. Its totient is φ = 521790.

The previous prime is 521789. The next prime is 521809. The reversal of 521791 is 197125.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 521791 - 2¹ = 521789 is a prime.

Together with 521789, it forms a pair of twin primes.

521791 is a lucky number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (521491) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 260895 + 260896.

It is an arithmetic number, because the mean of its divisors is an integer number (260896).

2⁵²¹⁷⁹¹ is an apocalyptic number.

521791 is a deficient number, since it is larger than the sum of its proper divisors (1).

521791 is an equidigital number, since it uses as much as digits as its factorization.

521791 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 630, while the sum is 25.

The square root of 521791 is about 722.3510227030. The cubic root of 521791 is about 80.5067314305.

The spelling of 521791 in words is "five hundred twenty-one thousand, seven hundred ninety-one".