18818257 has 2 divisors, whose sum is σ = 18818258. Its totient is φ = 18818256.

The previous prime is 18818251. The next prime is 18818287. The reversal of 18818257 is 75281881.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 14508481 + 4309776 = 3809^2 + 2076^2 .

It is a cyclic number.

It is not a de Polignac number, because 18818257 - 2¹¹ = 18816209 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (18818251) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9409128 + 9409129.

It is an arithmetic number, because the mean of its divisors is an integer number (9409129).

Almost surely, 2^18818257 is an apocalyptic number.

It is an amenable number.

18818257 is a deficient number, since it is larger than the sum of its proper divisors (1).

18818257 is an equidigital number, since it uses as much as digits as its factorization.

18818257 is an evil number, because the sum of its binary digits is even.

The product of its digits is 35840, while the sum is 40.

The square root of 18818257 is about 4338.0014983861. The cubic root of 18818257 is about 265.9866247255.

The spelling of 18818257 in words is "eighteen million, eight hundred eighteen thousand, two hundred fifty-seven".