19281918197 has 2 divisors, whose sum is σ = 19281918198. Its totient is φ = 19281918196.

The previous prime is 19281918179. The next prime is 19281918247. The reversal of 19281918197 is 79181918291.

Together with previous prime (19281918179) it forms an Ormiston pair, because they use the same digits, order apart.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 18644810116 + 637108081 = 136546^2 + 25241^2 .

It is a cyclic number.

It is not a de Polignac number, because 19281918197 - 2²⁴ = 19265140981 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (19281918137) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9640959098 + 9640959099.

It is an arithmetic number, because the mean of its divisors is an integer number (9640959099).

Almost surely, 2^19281918197 is an apocalyptic number.

It is an amenable number.

19281918197 is a deficient number, since it is larger than the sum of its proper divisors (1).

19281918197 is an equidigital number, since it uses as much as digits as its factorization.

19281918197 is an evil number, because the sum of its binary digits is even.

The product of its digits is 653184, while the sum is 56.

The spelling of 19281918197 in words is "nineteen billion, two hundred eighty-one million, nine hundred eighteen thousand, one hundred ninety-seven".