19906429438897 has 2 divisors, whose sum is σ = 19906429438898. Its totient is φ = 19906429438896.

The previous prime is 19906429438873. The next prime is 19906429438991. The reversal of 19906429438897 is 79883492460991.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 19893749778081 + 12679660816 = 4460241^2 + 112604^2 .

It is a cyclic number.

It is not a de Polignac number, because 19906429438897 - 2⁷ = 19906429438769 is a prime.

It is not a weakly prime, because it can be changed into another prime (19906429438867) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9953214719448 + 9953214719449.

It is an arithmetic number, because the mean of its divisors is an integer number (9953214719449).

Almost surely, 2^{19906429438897} is an apocalyptic number.

It is an amenable number.

19906429438897 is a deficient number, since it is larger than the sum of its proper divisors (1).

19906429438897 is an equidigital number, since it uses as much as digits as its factorization.

19906429438897 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1693052928, while the sum is 79.

The spelling of 19906429438897 in words is "nineteen trillion, nine hundred six billion, four hundred twenty-nine million, four hundred thirty-eight thousand, eight hundred ninety-seven".