18487321 has 2 divisors, whose sum is σ = 18487322. Its totient is φ = 18487320.

The previous prime is 18487307. The next prime is 18487363. The reversal of 18487321 is 12378481.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 18318400 + 168921 = 4280^2 + 411^2 .

It is a cyclic number.

It is not a de Polignac number, because 18487321 - 2⁵ = 18487289 is a prime.

It is not a weakly prime, because it can be changed into another prime (18487621) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9243660 + 9243661.

It is an arithmetic number, because the mean of its divisors is an integer number (9243661).

Almost surely, 2^18487321 is an apocalyptic number.

It is an amenable number.

18487321 is a deficient number, since it is larger than the sum of its proper divisors (1).

18487321 is an equidigital number, since it uses as much as digits as its factorization.

18487321 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 10752, while the sum is 34.

The square root of 18487321 is about 4299.6884770876. The cubic root of 18487321 is about 264.4181895657.

It can be divided in two parts, 18 and 487321, that multiplied together give a palindrome (8771778).

The spelling of 18487321 in words is "eighteen million, four hundred eighty-seven thousand, three hundred twenty-one".