1638118243 has 2 divisors, whose sum is σ = 1638118244. Its totient is φ = 1638118242.

The previous prime is 1638118219. The next prime is 1638118291. The reversal of 1638118243 is 3428118361.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 1638118243 - 2¹⁷ = 1637987171 is a prime.

It is a super-3 number, since 3×1638118243³ (a number of 29 digits) contains 333 as substring.

It is not a weakly prime, because it can be changed into another prime (1638118043) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 819059121 + 819059122.

It is an arithmetic number, because the mean of its divisors is an integer number (819059122).

Almost surely, 2^1638118243 is an apocalyptic number.

1638118243 is a deficient number, since it is larger than the sum of its proper divisors (1).

1638118243 is an equidigital number, since it uses as much as digits as its factorization.

1638118243 is an evil number, because the sum of its binary digits is even.

The product of its digits is 27648, while the sum is 37.

The square root of 1638118243 is about 40473.6734557169. The cubic root of 1638118243 is about 1178.8224974575.

It can be divided in two parts, 1638118 and 243, that added together give a palindrome (1638361).

The spelling of 1638118243 in words is "one billion, six hundred thirty-eight million, one hundred eighteen thousand, two hundred forty-three".