1218021853 has 2 divisors, whose sum is σ = 1218021854. Its totient is φ = 1218021852.

The previous prime is 1218021851. The next prime is 1218021869. The reversal of 1218021853 is 3581208121.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 669619129 + 548402724 = 25877^2 + 23418^2 .

It is a cyclic number.

It is not a de Polignac number, because 1218021853 - 2¹ = 1218021851 is a prime.

Together with 1218021851, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1218021851) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 609010926 + 609010927.

It is an arithmetic number, because the mean of its divisors is an integer number (609010927).

Almost surely, 2^1218021853 is an apocalyptic number.

It is an amenable number.

1218021853 is a deficient number, since it is larger than the sum of its proper divisors (1).

1218021853 is an equidigital number, since it uses as much as digits as its factorization.

1218021853 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 3840, while the sum is 31.

The square root of 1218021853 is about 34900.1698133405. The cubic root of 1218021853 is about 1067.9519016456.

Adding to 1218021853 its reverse (3581208121), we get a palindrome (4799229974).

The spelling of 1218021853 in words is "one billion, two hundred eighteen million, twenty-one thousand, eight hundred fifty-three".