18121603 has 2 divisors, whose sum is σ = 18121604. Its totient is φ = 18121602.

The previous prime is 18121589. The next prime is 18121613. The reversal of 18121603 is 30612181.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 18121603 - 2¹³ = 18113411 is a prime.

It is not a weakly prime, because it can be changed into another prime (18121613) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9060801 + 9060802.

It is an arithmetic number, because the mean of its divisors is an integer number (9060802).

Almost surely, 2^18121603 is an apocalyptic number.

18121603 is a deficient number, since it is larger than the sum of its proper divisors (1).

18121603 is an equidigital number, since it uses as much as digits as its factorization.

18121603 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 288, while the sum is 22.

The square root of 18121603 is about 4256.9476153695. The cubic root of 18121603 is about 262.6629820816.

Adding to 18121603 its reverse (30612181), we get a palindrome (48733784).

The spelling of 18121603 in words is "eighteen million, one hundred twenty-one thousand, six hundred three".