1638071819 has 2 divisors, whose sum is σ = 1638071820. Its totient is φ = 1638071818.

The previous prime is 1638071749. The next prime is 1638071821. The reversal of 1638071819 is 9181708361.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 1638071819 - 2¹² = 1638067723 is a prime.

It is a super-2 number, since 2×1638071819² = 5366558568403937522, which contains 22 as substring.

It is a Sophie Germain prime.

Together with 1638071821, it forms a pair of twin primes.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 1638071819.

It is not a weakly prime, because it can be changed into another prime (1638071849) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 819035909 + 819035910.

It is an arithmetic number, because the mean of its divisors is an integer number (819035910).

Almost surely, 2^1638071819 is an apocalyptic number.

1638071819 is a deficient number, since it is larger than the sum of its proper divisors (1).

1638071819 is an equidigital number, since it uses as much as digits as its factorization.

1638071819 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 72576, while the sum is 44.

The square root of 1638071819 is about 40473.0999430486. The cubic root of 1638071819 is about 1178.8113614741.

The spelling of 1638071819 in words is "one billion, six hundred thirty-eight million, seventy-one thousand, eight hundred nineteen".