19906429438991 has 2 divisors, whose sum is σ = 19906429438992. Its totient is φ = 19906429438990.

The previous prime is 19906429438897. The next prime is 19906429439003. The reversal of 19906429438991 is 19983492460991.

It is a strong prime.

It is an emirp because it is prime and its reverse (19983492460991) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 19906429438991 - 2⁴² = 15508382927887 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (19906429438591) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9953214719495 + 9953214719496.

It is an arithmetic number, because the mean of its divisors is an integer number (9953214719496).

Almost surely, 2^{19906429438991} is an apocalyptic number.

19906429438991 is a deficient number, since it is larger than the sum of its proper divisors (1).

19906429438991 is an equidigital number, since it uses as much as digits as its factorization.

19906429438991 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 272097792, while the sum is 74.

The spelling of 19906429438991 in words is "nineteen trillion, nine hundred six billion, four hundred twenty-nine million, four hundred thirty-eight thousand, nine hundred ninety-one".