521530831 has 2 divisors, whose sum is σ = 521530832. Its totient is φ = 521530830.

The previous prime is 521530787. The next prime is 521530853. The reversal of 521530831 is 138035125.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 521530831 - 2²⁵ = 487976399 is a prime.

It is a super-2 number, since 2×521530831² = 543988815367101122, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 521530831.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (521530931) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 260765415 + 260765416.

It is an arithmetic number, because the mean of its divisors is an integer number (260765416).

Almost surely, 2^521530831 is an apocalyptic number.

521530831 is a deficient number, since it is larger than the sum of its proper divisors (1).

521530831 is an equidigital number, since it uses as much as digits as its factorization.

521530831 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 3600, while the sum is 28.

The square root of 521530831 is about 22837.0495248401. The cubic root of 521530831 is about 804.9334878112.

Adding to 521530831 its reverse (138035125), we get a palindrome (659565956).

It can be divided in two parts, 5215 and 30831, that added together give a triangular number (36046 = T₂₆₈).

The spelling of 521530831 in words is "five hundred twenty-one million, five hundred thirty thousand, eight hundred thirty-one".