18520417 has 2 divisors, whose sum is σ = 18520418. Its totient is φ = 18520416.

The previous prime is 18520399. The next prime is 18520427. The reversal of 18520417 is 71402581.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 13133376 + 5387041 = 3624^2 + 2321^2 .

It is a cyclic number.

It is not a de Polignac number, because 18520417 - 2¹⁵ = 18487649 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (18520427) 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, 9260208 + 9260209.

It is an arithmetic number, because the mean of its divisors is an integer number (9260209).

Almost surely, 2^18520417 is an apocalyptic number.

It is an amenable number.

18520417 is a deficient number, since it is larger than the sum of its proper divisors (1).

18520417 is an equidigital number, since it uses as much as digits as its factorization.

18520417 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 2240, while the sum is 28.

The square root of 18520417 is about 4303.5354070810. The cubic root of 18520417 is about 264.5758826403.

Adding to 18520417 its reverse (71402581), we get a palindrome (89922998).

It can be divided in two parts, 185 and 20417, that added together give a palindrome (20602).

The spelling of 18520417 in words is "eighteen million, five hundred twenty thousand, four hundred seventeen".