20557171 has 2 divisors, whose sum is σ = 20557172. Its totient is φ = 20557170.

The previous prime is 20557157. The next prime is 20557181. The reversal of 20557171 is 17175502.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 20557171 - 2¹⁵ = 20524403 is a prime.

It is not a weakly prime, because it can be changed into another prime (20557181) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10278585 + 10278586.

It is an arithmetic number, because the mean of its divisors is an integer number (10278586).

Almost surely, 2^20557171 is an apocalyptic number.

20557171 is a deficient number, since it is larger than the sum of its proper divisors (1).

20557171 is an equidigital number, since it uses as much as digits as its factorization.

20557171 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 2450, while the sum is 28.

The square root of 20557171 is about 4534.0016541682. The cubic root of 20557171 is about 273.9393680109.

The spelling of 20557171 in words is "twenty million, five hundred fifty-seven thousand, one hundred seventy-one".