1305531257 has 2 divisors, whose sum is σ = 1305531258. Its totient is φ = 1305531256.

The previous prime is 1305531223. The next prime is 1305531263. The reversal of 1305531257 is 7521355031.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 925437241 + 380094016 = 30421^2 + 19496^2 .

It is an emirp because it is prime and its reverse (7521355031) is a distict prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1305531257 is a prime.

It is not a weakly prime, because it can be changed into another prime (1305531277) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 652765628 + 652765629.

It is an arithmetic number, because the mean of its divisors is an integer number (652765629).

Almost surely, 2^1305531257 is an apocalyptic number.

It is an amenable number.

1305531257 is a deficient number, since it is larger than the sum of its proper divisors (1).

1305531257 is an equidigital number, since it uses as much as digits as its factorization.

1305531257 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 15750, while the sum is 32.

The square root of 1305531257 is about 36132.1360702630. The cubic root of 1305531257 is about 1092.9385838105.

Adding to 1305531257 its reverse (7521355031), we get a palindrome (8826886288).

The spelling of 1305531257 in words is "one billion, three hundred five million, five hundred thirty-one thousand, two hundred fifty-seven".