1271855261 has 4 divisors (see below), whose sum is σ = 1271933472. Its totient is φ = 1271777052.

The previous prime is 1271855183. The next prime is 1271855267. The reversal of 1271855261 is 1625581721.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also a brilliant number, because the two primes have the same length.

It is a cyclic number.

It is not a de Polignac number, because 1271855261 - 2¹⁰ = 1271854237 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1271855267) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 4511 + ... + 50636.

It is an arithmetic number, because the mean of its divisors is an integer number (317983368).

Almost surely, 2^1271855261 is an apocalyptic number.

It is an amenable number.

1271855261 is a deficient number, since it is larger than the sum of its proper divisors (78211).

1271855261 is an equidigital number, since it uses as much as digits as its factorization.

1271855261 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 78210.

The product of its digits is 33600, while the sum is 38.

The square root of 1271855261 is about 35663.0798025072. The cubic root of 1271855261 is about 1083.4592048039.

The spelling of 1271855261 in words is "one billion, two hundred seventy-one million, eight hundred fifty-five thousand, two hundred sixty-one".