18052721 has 2 divisors, whose sum is σ = 18052722. Its totient is φ = 18052720.

The previous prime is 18052711. The next prime is 18052729. The reversal of 18052721 is 12725081.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 15366400 + 2686321 = 3920^2 + 1639^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-18052721 is a prime.

It is not a weakly prime, because it can be changed into another prime (18052729) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9026360 + 9026361.

It is an arithmetic number, because the mean of its divisors is an integer number (9026361).

Almost surely, 2^18052721 is an apocalyptic number.

It is an amenable number.

18052721 is a deficient number, since it is larger than the sum of its proper divisors (1).

18052721 is an equidigital number, since it uses as much as digits as its factorization.

18052721 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1120, while the sum is 26.

The square root of 18052721 is about 4248.8493736540. The cubic root of 18052721 is about 262.3297568849.

The spelling of 18052721 in words is "eighteen million, fifty-two thousand, seven hundred twenty-one".