19989579877 has 2 divisors, whose sum is σ = 19989579878. Its totient is φ = 19989579876.

The previous prime is 19989579847. The next prime is 19989579899. The reversal of 19989579877 is 77897598991.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 15889610916 + 4099968961 = 126054^2 + 64031^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-19989579877 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 19989579797 and 19989579806.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (19989579847) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9994789938 + 9994789939.

It is an arithmetic number, because the mean of its divisors is an integer number (9994789939).

Almost surely, 2^19989579877 is an apocalyptic number.

It is an amenable number.

19989579877 is a deficient number, since it is larger than the sum of its proper divisors (1).

19989579877 is an equidigital number, since it uses as much as digits as its factorization.

19989579877 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 720135360, while the sum is 79.

The spelling of 19989579877 in words is "nineteen billion, nine hundred eighty-nine million, five hundred seventy-nine thousand, eight hundred seventy-seven".