19778698641599 has 2 divisors, whose sum is σ = 19778698641600. Its totient is φ = 19778698641598.

The previous prime is 19778698641587. The next prime is 19778698641613. The reversal of 19778698641599 is 99514689687791.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-19778698641599 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (19778698641799) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9889349320799 + 9889349320800.

It is an arithmetic number, because the mean of its divisors is an integer number (9889349320800).

Almost surely, 2^{19778698641599} is an apocalyptic number.

19778698641599 is a deficient number, since it is larger than the sum of its proper divisors (1).

19778698641599 is an equidigital number, since it uses as much as digits as its factorization.

19778698641599 is an evil number, because the sum of its binary digits is even.

The product of its digits is 14814213120, while the sum is 89.

The spelling of 19778698641599 in words is "nineteen trillion, seven hundred seventy-eight billion, six hundred ninety-eight million, six hundred forty-one thousand, five hundred ninety-nine".