18518257 has 2 divisors, whose sum is σ = 18518258. Its totient is φ = 18518256.

The previous prime is 18518239. The next prime is 18518261. The reversal of 18518257 is 75281581.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 13278736 + 5239521 = 3644^2 + 2289^2 .

It is a cyclic number.

It is not a de Polignac number, because 18518257 - 2²³ = 10129649 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (18518207) 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, 9259128 + 9259129.

It is an arithmetic number, because the mean of its divisors is an integer number (9259129).

Almost surely, 2^18518257 is an apocalyptic number.

It is an amenable number.

18518257 is a deficient number, since it is larger than the sum of its proper divisors (1).

18518257 is an equidigital number, since it uses as much as digits as its factorization.

18518257 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 22400, while the sum is 37.

The square root of 18518257 is about 4303.2844433061. The cubic root of 18518257 is about 264.5655965845.

The spelling of 18518257 in words is "eighteen million, five hundred eighteen thousand, two hundred fifty-seven".