18973509 has 16 divisors (see below), whose sum is σ = 25804800. Its totient is φ = 12398256.

The previous prime is 18973499. The next prime is 18973517. The reversal of 18973509 is 90537981.

It is a happy number.

It is not a de Polignac number, because 18973509 - 2⁹ = 18972997 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18973589) 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, 52672 + ... + 53030.

It is an arithmetic number, because the mean of its divisors is an integer number (1612800).

Almost surely, 2^18973509 is an apocalyptic number.

It is an amenable number.

18973509 is a deficient number, since it is larger than the sum of its proper divisors (6831291).

18973509 is a wasteful number, since it uses less digits than its factorization.

18973509 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 664.

The product of its (nonzero) digits is 68040, while the sum is 42.

The square root of 18973509 is about 4355.8591575027. The cubic root of 18973509 is about 266.7160920540.

The spelling of 18973509 in words is "eighteen million, nine hundred seventy-three thousand, five hundred nine".