521831 has 2 divisors, whose sum is σ = 521832. Its totient is φ = 521830.

The previous prime is 521819. The next prime is 521861. The reversal of 521831 is 138125.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 521831 - 2⁶ = 521767 is a prime.

It is a super-2 number, since 2×521831² = 544615185122, which contains 22 as substring.

It is a Sophie Germain prime.

It is a congruent number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 521831.

It is not a weakly prime, because it can be changed into another prime (521861) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 260915 + 260916.

It is an arithmetic number, because the mean of its divisors is an integer number (260916).

2⁵²¹⁸³¹ is an apocalyptic number.

521831 is a deficient number, since it is larger than the sum of its proper divisors (1).

521831 is an equidigital number, since it uses as much as digits as its factorization.

521831 is an evil number, because the sum of its binary digits is even.

The product of its digits is 240, while the sum is 20.

The square root of 521831 is about 722.3787095423. The cubic root of 521831 is about 80.5087885676.

Adding to 521831 its reverse (138125), we get a palindrome (659956).

The spelling of 521831 in words is "five hundred twenty-one thousand, eight hundred thirty-one".