531631561 has 2 divisors, whose sum is σ = 531631562. Its totient is φ = 531631560.

The previous prime is 531631549. The next prime is 531631601. The reversal of 531631561 is 165136135.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 461390400 + 70241161 = 21480^2 + 8381^2 .

It is a cyclic number.

It is not a de Polignac number, because 531631561 - 2¹³ = 531623369 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (531631861) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 265815780 + 265815781.

It is an arithmetic number, because the mean of its divisors is an integer number (265815781).

Almost surely, 2^531631561 is an apocalyptic number.

It is an amenable number.

531631561 is a deficient number, since it is larger than the sum of its proper divisors (1).

531631561 is an equidigital number, since it uses as much as digits as its factorization.

531631561 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 8100, while the sum is 31.

The square root of 531631561 is about 23057.1368777652. The cubic root of 531631561 is about 810.0968034486.

Adding to 531631561 its reverse (165136135), we get a palindrome (696767696).

The spelling of 531631561 in words is "five hundred thirty-one million, six hundred thirty-one thousand, five hundred sixty-one".