19816847893 has 2 divisors, whose sum is σ = 19816847894. Its totient is φ = 19816847892.

The previous prime is 19816847881. The next prime is 19816847927. The reversal of 19816847893 is 39874861891.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 18906800004 + 910047889 = 137502^2 + 30167^2 .

It is an emirp because it is prime and its reverse (39874861891) is a distict prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-19816847893 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (19816847593) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9908423946 + 9908423947.

It is an arithmetic number, because the mean of its divisors is an integer number (9908423947).

Almost surely, 2^19816847893 is an apocalyptic number.

It is an amenable number.

19816847893 is a deficient number, since it is larger than the sum of its proper divisors (1).

19816847893 is an equidigital number, since it uses as much as digits as its factorization.

19816847893 is an evil number, because the sum of its binary digits is even.

The product of its digits is 20901888, while the sum is 64.

The spelling of 19816847893 in words is "nineteen billion, eight hundred sixteen million, eight hundred forty-seven thousand, eight hundred ninety-three".