18809493 has 4 divisors (see below), whose sum is σ = 25079328. Its totient is φ = 12539660.

The previous prime is 18809473. The next prime is 18809509. The reversal of 18809493 is 39490881.

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.

It is a cyclic number.

It is not a de Polignac number, because 18809493 - 2⁸ = 18809237 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18809443) 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, 3134913 + ... + 3134918.

It is an arithmetic number, because the mean of its divisors is an integer number (6269832).

Almost surely, 2^18809493 is an apocalyptic number.

It is an amenable number.

18809493 is a deficient number, since it is larger than the sum of its proper divisors (6269835).

18809493 is an equidigital number, since it uses as much as digits as its factorization.

18809493 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6269834.

The product of its (nonzero) digits is 62208, while the sum is 42.

The square root of 18809493 is about 4336.9912381742. The cubic root of 18809493 is about 265.9453267323.

The spelling of 18809493 in words is "eighteen million, eight hundred nine thousand, four hundred ninety-three".