531664561 has 2 divisors, whose sum is σ = 531664562. Its totient is φ = 531664560.

The previous prime is 531664501. The next prime is 531664591. The reversal of 531664561 is 165466135.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 436016161 + 95648400 = 20881^2 + 9780^2 .

It is a cyclic number.

It is not a de Polignac number, because 531664561 - 2¹³ = 531656369 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 531664561.

It is not a weakly prime, because it can be changed into another prime (531664501) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 265832280 + 265832281.

It is an arithmetic number, because the mean of its divisors is an integer number (265832281).

Almost surely, 2^531664561 is an apocalyptic number.

It is an amenable number.

531664561 is a deficient number, since it is larger than the sum of its proper divisors (1).

531664561 is an equidigital number, since it uses as much as digits as its factorization.

531664561 is an evil number, because the sum of its binary digits is even.

The product of its digits is 64800, while the sum is 37.

The square root of 531664561 is about 23057.8524802289. The cubic root of 531664561 is about 810.1135648320.

The spelling of 531664561 in words is "five hundred thirty-one million, six hundred sixty-four thousand, five hundred sixty-one".