18940656617 has 2 divisors, whose sum is σ = 18940656618. Its totient is φ = 18940656616.

The previous prime is 18940656611. The next prime is 18940656619. The reversal of 18940656617 is 71665604981.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 13663505881 + 5277150736 = 116891^2 + 72644^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-18940656617 is a prime.

Together with 18940656619, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (18940656611) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9470328308 + 9470328309.

It is an arithmetic number, because the mean of its divisors is an integer number (9470328309).

Almost surely, 2^18940656617 is an apocalyptic number.

It is an amenable number.

18940656617 is a deficient number, since it is larger than the sum of its proper divisors (1).

18940656617 is an equidigital number, since it uses as much as digits as its factorization.

18940656617 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 2177280, while the sum is 53.

The spelling of 18940656617 in words is "eighteen billion, nine hundred forty million, six hundred fifty-six thousand, six hundred seventeen".