1243938191 has 2 divisors, whose sum is σ = 1243938192. Its totient is φ = 1243938190.

The previous prime is 1243938173. The next prime is 1243938197. The reversal of 1243938191 is 1918393421.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 1243938191 - 2¹⁸ = 1243676047 is a prime.

It is a Sophie Germain prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1243938197) 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, 621969095 + 621969096.

It is an arithmetic number, because the mean of its divisors is an integer number (621969096).

Almost surely, 2^1243938191 is an apocalyptic number.

1243938191 is a deficient number, since it is larger than the sum of its proper divisors (1).

1243938191 is an equidigital number, since it uses as much as digits as its factorization.

1243938191 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 46656, while the sum is 41.

The square root of 1243938191 is about 35269.5079495022. The cubic root of 1243938191 is about 1075.4732197433.

The spelling of 1243938191 in words is "one billion, two hundred forty-three million, nine hundred thirty-eight thousand, one hundred ninety-one".