18216817 has 2 divisors, whose sum is σ = 18216818. Its totient is φ = 18216816.

The previous prime is 18216811. The next prime is 18216823. The reversal of 18216817 is 71861281.

It is a balanced prime because it is at equal distance from previous prime (18216811) and next prime (18216823).

It can be written as a sum of positive squares in only one way, i.e., 15397776 + 2819041 = 3924^2 + 1679^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-18216817 is a prime.

It is a super-2 number, since 2×18216817² = 663704843222978, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (18216811) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9108408 + 9108409.

It is an arithmetic number, because the mean of its divisors is an integer number (9108409).

Almost surely, 2^18216817 is an apocalyptic number.

It is an amenable number.

18216817 is a deficient number, since it is larger than the sum of its proper divisors (1).

18216817 is an equidigital number, since it uses as much as digits as its factorization.

18216817 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 5376, while the sum is 34.

The square root of 18216817 is about 4268.1163292488. The cubic root of 18216817 is about 263.1222041443.

The spelling of 18216817 in words is "eighteen million, two hundred sixteen thousand, eight hundred seventeen".