18624989 has 4 divisors (see below), whose sum is σ = 19267260. Its totient is φ = 17982720.

The previous prime is 18624973. The next prime is 18625003. The reversal of 18624989 is 98942681.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 98942681 = 79 ⋅1252439.

It can be written as a sum of positive squares in 2 ways, for example, as 12020089 + 6604900 = 3467^2 + 2570^2 .

It is a cyclic number.

It is not a de Polignac number, because 18624989 - 2⁴ = 18624973 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18624929) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 321092 + ... + 321149.

It is an arithmetic number, because the mean of its divisors is an integer number (4816815).

Almost surely, 2^18624989 is an apocalyptic number.

It is an amenable number.

18624989 is a deficient number, since it is larger than the sum of its proper divisors (642271).

18624989 is an equidigital number, since it uses as much as digits as its factorization.

18624989 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 642270.

The product of its digits is 248832, while the sum is 47.

The square root of 18624989 is about 4315.6678509820. The cubic root of 18624989 is about 265.0729074346.

The spelling of 18624989 in words is "eighteen million, six hundred twenty-four thousand, nine hundred eighty-nine".