1638281243 has 2 divisors, whose sum is σ = 1638281244. Its totient is φ = 1638281242.

The previous prime is 1638281233. The next prime is 1638281339. The reversal of 1638281243 is 3421828361.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 1638281243 - 2¹⁶ = 1638215707 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 1638281197 and 1638281206.

It is not a weakly prime, because it can be changed into another prime (1638281233) 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, 819140621 + 819140622.

It is an arithmetic number, because the mean of its divisors is an integer number (819140622).

Almost surely, 2^1638281243 is an apocalyptic number.

1638281243 is a deficient number, since it is larger than the sum of its proper divisors (1).

1638281243 is an equidigital number, since it uses as much as digits as its factorization.

1638281243 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 55296, while the sum is 38.

The square root of 1638281243 is about 40475.6870602588. The cubic root of 1638281243 is about 1178.8615955090.

The spelling of 1638281243 in words is "one billion, six hundred thirty-eight million, two hundred eighty-one thousand, two hundred forty-three".