1251273391 has 2 divisors, whose sum is σ = 1251273392. Its totient is φ = 1251273390.

The previous prime is 1251273379. The next prime is 1251273407. The reversal of 1251273391 is 1933721521.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 1251273391 - 2¹³ = 1251265199 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1251273341) 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, 625636695 + 625636696.

It is an arithmetic number, because the mean of its divisors is an integer number (625636696).

Almost surely, 2^1251273391 is an apocalyptic number.

1251273391 is a deficient number, since it is larger than the sum of its proper divisors (1).

1251273391 is an equidigital number, since it uses as much as digits as its factorization.

1251273391 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 11340, while the sum is 34.

The square root of 1251273391 is about 35373.3429435218. The cubic root of 1251273391 is about 1077.5830125732.

The spelling of 1251273391 in words is "one billion, two hundred fifty-one million, two hundred seventy-three thousand, three hundred ninety-one".