18640921417 has 2 divisors, whose sum is σ = 18640921418. Its totient is φ = 18640921416.

The previous prime is 18640921399. The next prime is 18640921423. The reversal of 18640921417 is 71412904681.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 16265431296 + 2375490121 = 127536^2 + 48739^2 .

It is a cyclic number.

It is not a de Polignac number, because 18640921417 - 2⁷ = 18640921289 is a prime.

It is not a weakly prime, because it can be changed into another prime (18670921417) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9320460708 + 9320460709.

It is an arithmetic number, because the mean of its divisors is an integer number (9320460709).

Almost surely, 2^18640921417 is an apocalyptic number.

It is an amenable number.

18640921417 is a deficient number, since it is larger than the sum of its proper divisors (1).

18640921417 is an equidigital number, since it uses as much as digits as its factorization.

18640921417 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 96768, while the sum is 43.

The spelling of 18640921417 in words is "eighteen billion, six hundred forty million, nine hundred twenty-one thousand, four hundred seventeen".