1279940191 has 2 divisors, whose sum is σ = 1279940192. Its totient is φ = 1279940190.

The previous prime is 1279940177. The next prime is 1279940203. The reversal of 1279940191 is 1910499721.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1279940191 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1279940131) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 639970095 + 639970096.

It is an arithmetic number, because the mean of its divisors is an integer number (639970096).

Almost surely, 2^1279940191 is an apocalyptic number.

1279940191 is a deficient number, since it is larger than the sum of its proper divisors (1).

1279940191 is an equidigital number, since it uses as much as digits as its factorization.

1279940191 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 40824, while the sum is 43.

The square root of 1279940191 is about 35776.2517740470. The cubic root of 1279940191 is about 1085.7501352701.

The spelling of 1279940191 in words is "one billion, two hundred seventy-nine million, nine hundred forty thousand, one hundred ninety-one".