18818251 has 2 divisors, whose sum is σ = 18818252. Its totient is φ = 18818250.

The previous prime is 18818213. The next prime is 18818257. The reversal of 18818251 is 15281881.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 18818251 - 2⁹ = 18817739 is a prime.

It is not a weakly prime, because it can be changed into another prime (18818257) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9409125 + 9409126.

It is an arithmetic number, because the mean of its divisors is an integer number (9409126).

Almost surely, 2^18818251 is an apocalyptic number.

18818251 is a deficient number, since it is larger than the sum of its proper divisors (1).

18818251 is an equidigital number, since it uses as much as digits as its factorization.

18818251 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 5120, while the sum is 34.

The square root of 18818251 is about 4338.0008068233. Note that the first 3 decimals coincide. The cubic root of 18818251 is about 265.9865964565.

The spelling of 18818251 in words is "eighteen million, eight hundred eighteen thousand, two hundred fifty-one".