1267931257 has 2 divisors, whose sum is σ = 1267931258. Its totient is φ = 1267931256.

The previous prime is 1267931221. The next prime is 1267931263. The reversal of 1267931257 is 7521397621.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1196883216 + 71048041 = 34596^2 + 8429^2 .

It is an emirp because it is prime and its reverse (7521397621) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 1267931257 - 2¹⁹ = 1267406969 is a prime.

It is not a weakly prime, because it can be changed into another prime (1267931657) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 633965628 + 633965629.

It is an arithmetic number, because the mean of its divisors is an integer number (633965629).

Almost surely, 2^1267931257 is an apocalyptic number.

It is an amenable number.

1267931257 is a deficient number, since it is larger than the sum of its proper divisors (1).

1267931257 is an equidigital number, since it uses as much as digits as its factorization.

1267931257 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 158760, while the sum is 43.

The square root of 1267931257 is about 35608.0223685618. The cubic root of 1267931257 is about 1082.3438058484.

The spelling of 1267931257 in words is "one billion, two hundred sixty-seven million, nine hundred thirty-one thousand, two hundred fifty-seven".