19905439419497 has 2 divisors, whose sum is σ = 19905439419498. Its totient is φ = 19905439419496.

The previous prime is 19905439419421. The next prime is 19905439419553. The reversal of 19905439419497 is 79491493450991.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 19905196402576 + 243016921 = 4461524^2 + 15589^2 .

It is a cyclic number.

It is not a de Polignac number, because 19905439419497 - 2³⁶ = 19836719942761 is a prime.

It is not a weakly prime, because it can be changed into another prime (19905439419997) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9952719709748 + 9952719709749.

It is an arithmetic number, because the mean of its divisors is an integer number (9952719709749).

Almost surely, 2^{19905439419497} is an apocalyptic number.

It is an amenable number.

19905439419497 is a deficient number, since it is larger than the sum of its proper divisors (1).

19905439419497 is an equidigital number, since it uses as much as digits as its factorization.

19905439419497 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 396809280, while the sum is 74.

The spelling of 19905439419497 in words is "nineteen trillion, nine hundred five billion, four hundred thirty-nine million, four hundred nineteen thousand, four hundred ninety-seven".