18621716317 has 2 divisors, whose sum is σ = 18621716318. Its totient is φ = 18621716316.

The previous prime is 18621716287. The next prime is 18621716339. The reversal of 18621716317 is 71361712681.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 18087829081 + 533887236 = 134491^2 + 23106^2 .

It is a cyclic number.

It is not a de Polignac number, because 18621716317 - 2³¹ = 16474232669 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (18621716387) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9310858158 + 9310858159.

It is an arithmetic number, because the mean of its divisors is an integer number (9310858159).

Almost surely, 2^18621716317 is an apocalyptic number.

It is an amenable number.

18621716317 is a deficient number, since it is larger than the sum of its proper divisors (1).

18621716317 is an equidigital number, since it uses as much as digits as its factorization.

18621716317 is an evil number, because the sum of its binary digits is even.

The product of its digits is 84672, while the sum is 43.

The spelling of 18621716317 in words is "eighteen billion, six hundred twenty-one million, seven hundred sixteen thousand, three hundred seventeen".