1218679381 has 2 divisors, whose sum is σ = 1218679382. Its totient is φ = 1218679380.

The previous prime is 1218679369. The next prime is 1218679421. The reversal of 1218679381 is 1839768121.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1218359025 + 320356 = 34905^2 + 566^2 .

It is a cyclic number.

It is not a de Polignac number, because 1218679381 - 2¹³ = 1218671189 is a prime.

It is a super-2 number, since 2×1218679381² = 2970358867349086322, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1218679321) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 609339690 + 609339691.

It is an arithmetic number, because the mean of its divisors is an integer number (609339691).

Almost surely, 2^1218679381 is an apocalyptic number.

It is an amenable number.

1218679381 is a deficient number, since it is larger than the sum of its proper divisors (1).

1218679381 is an equidigital number, since it uses as much as digits as its factorization.

1218679381 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 145152, while the sum is 46.

The square root of 1218679381 is about 34909.5886684447. The cubic root of 1218679381 is about 1068.1440388545.

The spelling of 1218679381 in words is "one billion, two hundred eighteen million, six hundred seventy-nine thousand, three hundred eighty-one".