18298921 has 4 divisors (see below), whose sum is σ = 18345412. Its totient is φ = 18252432.

The previous prime is 18298879. The next prime is 18298937. The reversal of 18298921 is 12989281.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 10653696 + 7645225 = 3264^2 + 2765^2 .

It is a cyclic number.

It is not a de Polignac number, because 18298921 - 2⁷ = 18298793 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (18298981) 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 in 3 ways as a sum of consecutive naturals, for example, 22650 + ... + 23443.

It is an arithmetic number, because the mean of its divisors is an integer number (4586353).

Almost surely, 2^18298921 is an apocalyptic number.

It is an amenable number.

18298921 is a deficient number, since it is larger than the sum of its proper divisors (46491).

18298921 is an equidigital number, since it uses as much as digits as its factorization.

18298921 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 46490.

The product of its digits is 20736, while the sum is 40.

The square root of 18298921 is about 4277.7238106264. The cubic root of 18298921 is about 263.5169128845.

The spelling of 18298921 in words is "eighteen million, two hundred ninety-eight thousand, nine hundred twenty-one".