1265660647 has 2 divisors, whose sum is σ = 1265660648. Its totient is φ = 1265660646.

The previous prime is 1265660633. The next prime is 1265660677. The reversal of 1265660647 is 7460665621.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 1265660647 - 2¹⁹ = 1265136359 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1265660677) 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, 632830323 + 632830324.

It is an arithmetic number, because the mean of its divisors is an integer number (632830324).

Almost surely, 2^1265660647 is an apocalyptic number.

1265660647 is a deficient number, since it is larger than the sum of its proper divisors (1).

1265660647 is an equidigital number, since it uses as much as digits as its factorization.

1265660647 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 362880, while the sum is 43.

The square root of 1265660647 is about 35576.1246765299. The cubic root of 1265660647 is about 1081.6973330664.

The spelling of 1265660647 in words is "one billion, two hundred sixty-five million, six hundred sixty thousand, six hundred forty-seven".