1218787231 has 2 divisors, whose sum is σ = 1218787232. Its totient is φ = 1218787230.

The previous prime is 1218787187. The next prime is 1218787247. The reversal of 1218787231 is 1327878121.

It is a strong prime.

It is an emirp because it is prime and its reverse (1327878121) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 1218787231 - 2⁹ = 1218786719 is a prime.

It is a super-2 number, since 2×1218787231² = 2970884628897294722, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1218787261) 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, 609393615 + 609393616.

It is an arithmetic number, because the mean of its divisors is an integer number (609393616).

Almost surely, 2^1218787231 is an apocalyptic number.

1218787231 is a deficient number, since it is larger than the sum of its proper divisors (1).

1218787231 is an equidigital number, since it uses as much as digits as its factorization.

1218787231 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 37632, while the sum is 40.

The square root of 1218787231 is about 34911.1333388076. The cubic root of 1218787231 is about 1068.1755472611.

The spelling of 1218787231 in words is "one billion, two hundred eighteen million, seven hundred eighty-seven thousand, two hundred thirty-one".