531320561 has 2 divisors, whose sum is σ = 531320562. Its totient is φ = 531320560.

The previous prime is 531320557. The next prime is 531320597. The reversal of 531320561 is 165023135.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 451307536 + 80013025 = 21244^2 + 8945^2 .

It is a cyclic number.

It is not a de Polignac number, because 531320561 - 2² = 531320557 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 531320561.

It is not a weakly prime, because it can be changed into another prime (531320521) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 265660280 + 265660281.

It is an arithmetic number, because the mean of its divisors is an integer number (265660281).

Almost surely, 2^531320561 is an apocalyptic number.

It is an amenable number.

531320561 is a deficient number, since it is larger than the sum of its proper divisors (1).

531320561 is an equidigital number, since it uses as much as digits as its factorization.

531320561 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 2700, while the sum is 26.

The square root of 531320561 is about 23050.3917754124. The cubic root of 531320561 is about 809.9388060258.

Adding to 531320561 its reverse (165023135), we get a palindrome (696343696).

The spelling of 531320561 in words is "five hundred thirty-one million, three hundred twenty thousand, five hundred sixty-one".