18705871 has 2 divisors, whose sum is σ = 18705872. Its totient is φ = 18705870.

The previous prime is 18705821. The next prime is 18705887. The reversal of 18705871 is 17850781.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 18705871 - 2¹⁵ = 18673103 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 18705871.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (18705821) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9352935 + 9352936.

It is an arithmetic number, because the mean of its divisors is an integer number (9352936).

Almost surely, 2^18705871 is an apocalyptic number.

18705871 is a deficient number, since it is larger than the sum of its proper divisors (1).

18705871 is an equidigital number, since it uses as much as digits as its factorization.

18705871 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 15680, while the sum is 37.

The square root of 18705871 is about 4325.0284392129. The cubic root of 18705871 is about 265.4560605299.

The spelling of 18705871 in words is "eighteen million, seven hundred five thousand, eight hundred seventy-one".