1261856273 has 2 divisors, whose sum is σ = 1261856274. Its totient is φ = 1261856272.

The previous prime is 1261856213. The next prime is 1261856293. The reversal of 1261856273 is 3726581621.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1142980864 + 118875409 = 33808^2 + 10903^2 .

It is a cyclic number.

It is not a de Polignac number, because 1261856273 - 2⁸ = 1261856017 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 1261856273.

It is not a weakly prime, because it can be changed into another prime (1261856213) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 630928136 + 630928137.

It is an arithmetic number, because the mean of its divisors is an integer number (630928137).

Almost surely, 2^1261856273 is an apocalyptic number.

It is an amenable number.

1261856273 is a deficient number, since it is larger than the sum of its proper divisors (1).

1261856273 is an equidigital number, since it uses as much as digits as its factorization.

1261856273 is an evil number, because the sum of its binary digits is even.

The product of its digits is 120960, while the sum is 41.

The square root of 1261856273 is about 35522.6163591591. The cubic root of 1261856273 is about 1080.6124421278.

The spelling of 1261856273 in words is "one billion, two hundred sixty-one million, eight hundred fifty-six thousand, two hundred seventy-three".