1861800019 has 2 divisors, whose sum is σ = 1861800020. Its totient is φ = 1861800018.

The previous prime is 1861799993. The next prime is 1861800023. The reversal of 1861800019 is 9100081681.

It is a strong prime.

It is an emirp because it is prime and its reverse (9100081681) is a distict prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1861800019 is a prime.

It is a super-2 number, since 2×1861800019² = 6932598621496800722, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (1861800079) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 930900009 + 930900010.

It is an arithmetic number, because the mean of its divisors is an integer number (930900010).

Almost surely, 2^1861800019 is an apocalyptic number.

1861800019 is a deficient number, since it is larger than the sum of its proper divisors (1).

1861800019 is an equidigital number, since it uses as much as digits as its factorization.

1861800019 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 3456, while the sum is 34.

The square root of 1861800019 is about 43148.5807298456. The cubic root of 1861800019 is about 1230.2055353093.

The spelling of 1861800019 in words is "one billion, eight hundred sixty-one million, eight hundred thousand, nineteen".