18287389 has 2 divisors, whose sum is σ = 18287390. Its totient is φ = 18287388.

The previous prime is 18287333. The next prime is 18287407. The reversal of 18287389 is 98378281.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 11088900 + 7198489 = 3330^2 + 2683^2 .

It is a cyclic number.

It is not a de Polignac number, because 18287389 - 2⁷ = 18287261 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 (18287309) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9143694 + 9143695.

It is an arithmetic number, because the mean of its divisors is an integer number (9143695).

Almost surely, 2^18287389 is an apocalyptic number.

It is an amenable number.

18287389 is a deficient number, since it is larger than the sum of its proper divisors (1).

18287389 is an equidigital number, since it uses as much as digits as its factorization.

18287389 is an evil number, because the sum of its binary digits is even.

The product of its digits is 193536, while the sum is 46.

The square root of 18287389 is about 4276.3756850866. The cubic root of 18287389 is about 263.4615450365.

It can be divided in two parts, 182 and 87389, that added together give a triangular number (87571 = T₄₁₈).

The spelling of 18287389 in words is "eighteen million, two hundred eighty-seven thousand, three hundred eighty-nine".