181603 has 2 divisors, whose sum is σ = 181604. Its totient is φ = 181602.

The previous prime is 181553. The next prime is 181607. The reversal of 181603 is 306181.

181603 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-181603 is a prime.

It is not a weakly prime, because it can be changed into another prime (181607) by changing a digit.

It is a good prime.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 90801 + 90802.

It is an arithmetic number, because the mean of its divisors is an integer number (90802).

2¹⁸¹⁶⁰³ is an apocalyptic number.

181603 is a deficient number, since it is larger than the sum of its proper divisors (1).

181603 is an equidigital number, since it uses as much as digits as its factorization.

181603 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 144, while the sum is 19.

The square root of 181603 is about 426.1490349631. The cubic root of 181603 is about 56.6292756023.

Adding to 181603 its reverse (306181), we get a palindrome (487784).

It can be divided in two parts, 181 and 603, that added together give a square (784 = 28²).

The spelling of 181603 in words is "one hundred eighty-one thousand, six hundred three".