18381287 has 2 divisors, whose sum is σ = 18381288. Its totient is φ = 18381286.

The previous prime is 18381271. The next prime is 18381317. The reversal of 18381287 is 78218381.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 18381287 - 2⁴ = 18381271 is a prime.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 18381287.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (18381217) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9190643 + 9190644.

It is an arithmetic number, because the mean of its divisors is an integer number (9190644).

Almost surely, 2^18381287 is an apocalyptic number.

18381287 is a deficient number, since it is larger than the sum of its proper divisors (1).

18381287 is an equidigital number, since it uses as much as digits as its factorization.

18381287 is an evil number, because the sum of its binary digits is even.

The product of its digits is 21504, while the sum is 38.

The square root of 18381287 is about 4287.3403177261. The cubic root of 18381287 is about 263.9116966305.

It can be divided in two parts, 1838 and 1287, that added together give a 5-th power (3125 = 5⁵).

The spelling of 18381287 in words is "eighteen million, three hundred eighty-one thousand, two hundred eighty-seven".