18428809 has 4 divisors (see below), whose sum is σ = 21061504. Its totient is φ = 15796116.

The previous prime is 18428807. The next prime is 18428857. The reversal of 18428809 is 90882481.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 90882481 = 1171 ⋅77611.

It is not a de Polignac number, because 18428809 - 2¹ = 18428807 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (18428801) 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, 1316337 + ... + 1316350.

It is an arithmetic number, because the mean of its divisors is an integer number (5265376).

Almost surely, 2^18428809 is an apocalyptic number.

It is an amenable number.

18428809 is a deficient number, since it is larger than the sum of its proper divisors (2632695).

18428809 is an equidigital number, since it uses as much as digits as its factorization.

18428809 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2632694.

The product of its (nonzero) digits is 36864, while the sum is 40.

The square root of 18428809 is about 4292.8788708744. The cubic root of 18428809 is about 264.1389353254.

It can be divided in two parts, 1842880 and 9, that multiplied together give a triangular number (16585920 = T₅₇₅₉).

The spelling of 18428809 in words is "eighteen million, four hundred twenty-eight thousand, eight hundred nine".