19851906443 has 2 divisors, whose sum is σ = 19851906444. Its totient is φ = 19851906442.

The previous prime is 19851906419. The next prime is 19851906457. The reversal of 19851906443 is 34460915891.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 19851906443 - 2²⁶ = 19784797579 is a prime.

It is a Sophie Germain prime.

It is a junction number, because it is equal to n+sod(n) for n = 19851906391 and 19851906400.

It is not a weakly prime, because it can be changed into another prime (19851906463) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9925953221 + 9925953222.

It is an arithmetic number, because the mean of its divisors is an integer number (9925953222).

Almost surely, 2^19851906443 is an apocalyptic number.

19851906443 is a deficient number, since it is larger than the sum of its proper divisors (1).

19851906443 is an equidigital number, since it uses as much as digits as its factorization.

19851906443 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 933120, while the sum is 50.

The spelling of 19851906443 in words is "nineteen billion, eight hundred fifty-one million, nine hundred six thousand, four hundred forty-three".