1265173009 has 2 divisors, whose sum is σ = 1265173010. Its totient is φ = 1265173008.

The previous prime is 1265172949. The next prime is 1265173027. The reversal of 1265173009 is 9003715621.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1197160000 + 68013009 = 34600^2 + 8247^2 .

It is a cyclic number.

It is not a de Polignac number, because 1265173009 - 2⁹ = 1265172497 is a prime.

It is a super-2 number, since 2×1265173009² = 3201325485404228162, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (1265173909) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 632586504 + 632586505.

It is an arithmetic number, because the mean of its divisors is an integer number (632586505).

Almost surely, 2^1265173009 is an apocalyptic number.

It is an amenable number.

1265173009 is a deficient number, since it is larger than the sum of its proper divisors (1).

1265173009 is an equidigital number, since it uses as much as digits as its factorization.

1265173009 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 11340, while the sum is 34.

The square root of 1265173009 is about 35569.2705716606. The cubic root of 1265173009 is about 1081.5583952233.

The spelling of 1265173009 in words is "one billion, two hundred sixty-five million, one hundred seventy-three thousand, nine".