18687329 has 2 divisors, whose sum is σ = 18687330. Its totient is φ = 18687328.

The previous prime is 18687311. The next prime is 18687373. The reversal of 18687329 is 92378681.

It is an a-pointer prime, because the next prime (18687373) can be obtained adding 18687329 to its sum of digits (44).

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 12816400 + 5870929 = 3580^2 + 2423^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-18687329 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 18687329.

It is not a weakly prime, because it can be changed into another prime (18687379) 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, 9343664 + 9343665.

It is an arithmetic number, because the mean of its divisors is an integer number (9343665).

Almost surely, 2^18687329 is an apocalyptic number.

It is an amenable number.

18687329 is a deficient number, since it is larger than the sum of its proper divisors (1).

18687329 is an equidigital number, since it uses as much as digits as its factorization.

18687329 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 145152, while the sum is 44.

The square root of 18687329 is about 4322.8843380317. The cubic root of 18687329 is about 265.3683213473.

The spelling of 18687329 in words is "eighteen million, six hundred eighty-seven thousand, three hundred twenty-nine".