1265186261 has 2 divisors, whose sum is σ = 1265186262. Its totient is φ = 1265186260.

The previous prime is 1265186243. The next prime is 1265186281. The reversal of 1265186261 is 1626815621.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 791296900 + 473889361 = 28130^2 + 21769^2 .

It is an emirp because it is prime and its reverse (1626815621) is a distict prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1265186261 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1265186281) 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, 632593130 + 632593131.

It is an arithmetic number, because the mean of its divisors is an integer number (632593131).

Almost surely, 2^1265186261 is an apocalyptic number.

It is an amenable number.

1265186261 is a deficient number, since it is larger than the sum of its proper divisors (1).

1265186261 is an equidigital number, since it uses as much as digits as its factorization.

1265186261 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 34560, while the sum is 38.

The square root of 1265186261 is about 35569.4568555664. The cubic root of 1265186261 is about 1081.5621714557.

The spelling of 1265186261 in words is "one billion, two hundred sixty-five million, one hundred eighty-six thousand, two hundred sixty-one".