18976367166221 has 2 divisors, whose sum is σ = 18976367166222. Its totient is φ = 18976367166220.

The previous prime is 18976367166139. The next prime is 18976367166241. The reversal of 18976367166221 is 12266176367981.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 18968376772900 + 7990393321 = 4355270^2 + 89389^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-18976367166221 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (18976367166241) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9488183583110 + 9488183583111.

It is an arithmetic number, because the mean of its divisors is an integer number (9488183583111).

Almost surely, 2^{18976367166221} is an apocalyptic number.

It is an amenable number.

18976367166221 is a deficient number, since it is larger than the sum of its proper divisors (1).

18976367166221 is an equidigital number, since it uses as much as digits as its factorization.

18976367166221 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 54867456, while the sum is 65.

The spelling of 18976367166221 in words is "eighteen trillion, nine hundred seventy-six billion, three hundred sixty-seven million, one hundred sixty-six thousand, two hundred twenty-one".