521812531 has 2 divisors, whose sum is σ = 521812532. Its totient is φ = 521812530.

The previous prime is 521812481. The next prime is 521812537. The reversal of 521812531 is 135218125.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 521812531 - 2¹¹ = 521810483 is a prime.

It is a super-2 number, since 2×521812531² = 544576635017251922, 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 521812531.

It is not a weakly prime, because it can be changed into another prime (521812537) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 260906265 + 260906266.

It is an arithmetic number, because the mean of its divisors is an integer number (260906266).

Almost surely, 2^521812531 is an apocalyptic number.

521812531 is a deficient number, since it is larger than the sum of its proper divisors (1).

521812531 is an equidigital number, since it uses as much as digits as its factorization.

521812531 is an evil number, because the sum of its binary digits is even.

The product of its digits is 2400, while the sum is 28.

The square root of 521812531 is about 22843.2163015631. The cubic root of 521812531 is about 805.0783874904.

The spelling of 521812531 in words is "five hundred twenty-one million, eight hundred twelve thousand, five hundred thirty-one".