17959181621 has 2 divisors, whose sum is σ = 17959181622. Its totient is φ = 17959181620.

The previous prime is 17959181561. The next prime is 17959181623. The reversal of 17959181621 is 12618195971.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 17738510596 + 220671025 = 133186^2 + 14855^2 .

It is a cyclic number.

It is not a de Polignac number, because 17959181621 - 2⁶ = 17959181557 is a prime.

Together with 17959181623, it forms a pair of twin primes.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 17959181621.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (17959181623) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 8979590810 + 8979590811.

It is an arithmetic number, because the mean of its divisors is an integer number (8979590811).

Almost surely, 2^17959181621 is an apocalyptic number.

It is an amenable number.

17959181621 is a deficient number, since it is larger than the sum of its proper divisors (1).

17959181621 is an equidigital number, since it uses as much as digits as its factorization.

17959181621 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 272160, while the sum is 50.

The spelling of 17959181621 in words is "seventeen billion, nine hundred fifty-nine million, one hundred eighty-one thousand, six hundred twenty-one".