1271723749 has 2 divisors, whose sum is σ = 1271723750. Its totient is φ = 1271723748.

The previous prime is 1271723737. The next prime is 1271723767. The reversal of 1271723749 is 9473271721.

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., 982383649 + 289340100 = 31343^2 + 17010^2 .

It is an emirp because it is prime and its reverse (9473271721) is a distict prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1271723749 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1271723779) 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 as a sum of consecutive naturals, namely, 635861874 + 635861875.

It is an arithmetic number, because the mean of its divisors is an integer number (635861875).

Almost surely, 2^1271723749 is an apocalyptic number.

It is an amenable number.

1271723749 is a deficient number, since it is larger than the sum of its proper divisors (1).

1271723749 is an equidigital number, since it uses as much as digits as its factorization.

1271723749 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 148176, while the sum is 43.

The square root of 1271723749 is about 35661.2359432480. The cubic root of 1271723749 is about 1083.4218596743.

The spelling of 1271723749 in words is "one billion, two hundred seventy-one million, seven hundred twenty-three thousand, seven hundred forty-nine".