20656720006171 has 2 divisors, whose sum is σ = 20656720006172. Its totient is φ = 20656720006170.

The previous prime is 20656720006163. The next prime is 20656720006177. The reversal of 20656720006171 is 17160002765602.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 20656720006171 - 2³ = 20656720006163 is a prime.

It is not a weakly prime, because it can be changed into another prime (20656720006177) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10328360003085 + 10328360003086.

It is an arithmetic number, because the mean of its divisors is an integer number (10328360003086).

Almost surely, 2^{20656720006171} is an apocalyptic number.

20656720006171 is a deficient number, since it is larger than the sum of its proper divisors (1).

20656720006171 is an equidigital number, since it uses as much as digits as its factorization.

20656720006171 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 211680, while the sum is 43.

The spelling of 20656720006171 in words is "twenty trillion, six hundred fifty-six billion, seven hundred twenty million, six thousand, one hundred seventy-one".