18643389 has 16 divisors (see below), whose sum is σ = 26265600. Its totient is φ = 11730096.

The previous prime is 18643367. The next prime is 18643403. The reversal of 18643389 is 98334681.

It is a happy number.

It is not a de Polignac number, because 18643389 - 2¹⁵ = 18610621 is a prime.

It is a super-4 number, since 4×18643389⁴ (a number of 30 digits) contains 4444 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 18643389.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18653389) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 21172 + ... + 22034.

It is an arithmetic number, because the mean of its divisors is an integer number (1641600).

Almost surely, 2^18643389 is an apocalyptic number.

18643389 is a gapful number since it is divisible by the number (19) formed by its first and last digit.

It is an amenable number.

18643389 is a deficient number, since it is larger than the sum of its proper divisors (7622211).

18643389 is a wasteful number, since it uses less digits than its factorization.

18643389 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1264.

The product of its digits is 124416, while the sum is 42.

The square root of 18643389 is about 4317.7990921302. The cubic root of 18643389 is about 265.1601689848.

It can be divided in two parts, 1864 and 3389, that added together give a triangular number (5253 = T₁₀₂).

The spelling of 18643389 in words is "eighteen million, six hundred forty-three thousand, three hundred eighty-nine".