264131561 has 2 divisors, whose sum is σ = 264131562. Its totient is φ = 264131560.

The previous prime is 264131519. The next prime is 264131579. The reversal of 264131561 is 165131462.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 261016336 + 3115225 = 16156^2 + 1765^2 .

It is a cyclic number.

It is not a de Polignac number, because 264131561 - 2²² = 259937257 is a prime.

It is not a weakly prime, because it can be changed into another prime (264031561) 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, 132065780 + 132065781.

It is an arithmetic number, because the mean of its divisors is an integer number (132065781).

Almost surely, 2^264131561 is an apocalyptic number.

It is an amenable number.

264131561 is a deficient number, since it is larger than the sum of its proper divisors (1).

264131561 is an equidigital number, since it uses as much as digits as its factorization.

264131561 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 4320, while the sum is 29.

The square root of 264131561 is about 16252.1248149280. The cubic root of 264131561 is about 641.6134105310.

Subtracting from 264131561 its reverse (165131462), we obtain a palindrome (99000099).

The spelling of 264131561 in words is "two hundred sixty-four million, one hundred thirty-one thousand, five hundred sixty-one".