19691969197 has 2 divisors, whose sum is σ = 19691969198. Its totient is φ = 19691969196.

The previous prime is 19691969147. The next prime is 19691969233. The reversal of 19691969197 is 79196919691.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 19614282601 + 77686596 = 140051^2 + 8814^2 .

It is an emirp because it is prime and its reverse (79196919691) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 19691969197 - 2¹¹ = 19691967149 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (19691969117) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9845984598 + 9845984599.

It is an arithmetic number, because the mean of its divisors is an integer number (9845984599).

Almost surely, 2^19691969197 is an apocalyptic number.

It is an amenable number.

19691969197 is a deficient number, since it is larger than the sum of its proper divisors (1).

19691969197 is an equidigital number, since it uses as much as digits as its factorization.

19691969197 is an evil number, because the sum of its binary digits is even.

The product of its digits is 14880348, while the sum is 67.

The spelling of 19691969197 in words is "nineteen billion, six hundred ninety-one million, nine hundred sixty-nine thousand, one hundred ninety-seven".