18280309 has 2 divisors, whose sum is σ = 18280310. Its totient is φ = 18280308.

The previous prime is 18280303. The next prime is 18280313. The reversal of 18280309 is 90308281.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 10745284 + 7535025 = 3278^2 + 2745^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-18280309 is a prime.

It is equal to p_1168087 and since 18280309 and 1168087 have the same sum of digits, it is a Honaker prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (18280303) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9140154 + 9140155.

It is an arithmetic number, because the mean of its divisors is an integer number (9140155).

Almost surely, 2^18280309 is an apocalyptic number.

It is an amenable number.

18280309 is a deficient number, since it is larger than the sum of its proper divisors (1).

18280309 is an equidigital number, since it uses as much as digits as its factorization.

18280309 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 3456, while the sum is 31.

The square root of 18280309 is about 4275.5478011595. The cubic root of 18280309 is about 263.4275407561.

The spelling of 18280309 in words is "eighteen million, two hundred eighty thousand, three hundred nine".