20986171 has 2 divisors, whose sum is σ = 20986172. Its totient is φ = 20986170.

The previous prime is 20986157. The next prime is 20986181. The reversal of 20986171 is 17168902.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 20986171 - 2¹¹ = 20984123 is a prime.

It is not a weakly prime, because it can be changed into another prime (20986151) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10493085 + 10493086.

It is an arithmetic number, because the mean of its divisors is an integer number (10493086).

Almost surely, 2^20986171 is an apocalyptic number.

20986171 is a deficient number, since it is larger than the sum of its proper divisors (1).

20986171 is an equidigital number, since it uses as much as digits as its factorization.

20986171 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 6048, while the sum is 34.

The square root of 20986171 is about 4581.0665788657. The cubic root of 20986171 is about 275.8318437644.

The spelling of 20986171 in words is "twenty million, nine hundred eighty-six thousand, one hundred seventy-one".