18121559 has 2 divisors, whose sum is σ = 18121560. Its totient is φ = 18121558.

The previous prime is 18121531. The next prime is 18121567. The reversal of 18121559 is 95512181.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-18121559 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (18121589) 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, 9060779 + 9060780.

It is an arithmetic number, because the mean of its divisors is an integer number (9060780).

Almost surely, 2^18121559 is an apocalyptic number.

18121559 is a deficient number, since it is larger than the sum of its proper divisors (1).

18121559 is an equidigital number, since it uses as much as digits as its factorization.

18121559 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 3600, while the sum is 32.

The square root of 18121559 is about 4256.9424473441. The cubic root of 18121559 is about 262.6627694959.

The spelling of 18121559 in words is "eighteen million, one hundred twenty-one thousand, five hundred fifty-nine".