18721472489197 has 2 divisors, whose sum is σ = 18721472489198. Its totient is φ = 18721472489196.

The previous prime is 18721472489191. The next prime is 18721472489221. The reversal of 18721472489197 is 79198427412781.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 18121078416996 + 600394072201 = 4256886^2 + 774851^2 .

It is a cyclic number.

It is not a de Polignac number, because 18721472489197 - 2²⁷ = 18721338271469 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (18721472489191) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9360736244598 + 9360736244599.

It is an arithmetic number, because the mean of its divisors is an integer number (9360736244599).

Almost surely, 2^{18721472489197} is an apocalyptic number.

It is an amenable number.

18721472489197 is a deficient number, since it is larger than the sum of its proper divisors (1).

18721472489197 is an equidigital number, since it uses as much as digits as its factorization.

18721472489197 is an evil number, because the sum of its binary digits is even.

The product of its digits is 113799168, while the sum is 70.

The spelling of 18721472489197 in words is "eighteen trillion, seven hundred twenty-one billion, four hundred seventy-two million, four hundred eighty-nine thousand, one hundred ninety-seven".