1818156643 has 2 divisors, whose sum is σ = 1818156644. Its totient is φ = 1818156642.

The previous prime is 1818156631. The next prime is 1818156661. The reversal of 1818156643 is 3466518181.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 1818156643 - 2⁵ = 1818156611 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 1818156643.

It is not a weakly prime, because it can be changed into another prime (1818154643) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 909078321 + 909078322.

It is an arithmetic number, because the mean of its divisors is an integer number (909078322).

Almost surely, 2^1818156643 is an apocalyptic number.

1818156643 is a deficient number, since it is larger than the sum of its proper divisors (1).

1818156643 is an equidigital number, since it uses as much as digits as its factorization.

1818156643 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 138240, while the sum is 43.

The square root of 1818156643 is about 42639.8480649263. The cubic root of 1818156643 is about 1220.5168111840.

The spelling of 1818156643 in words is "one billion, eight hundred eighteen million, one hundred fifty-six thousand, six hundred forty-three".