18909649 has 4 divisors (see below), whose sum is σ = 20628720. Its totient is φ = 17190580.

The previous prime is 18909629. The next prime is 18909673. The reversal of 18909649 is 94690981.

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 not a de Polignac number, because 18909649 - 2⁷ = 18909521 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 18909599 and 18909608.

It is not an unprimeable number, because it can be changed into a prime (18909619) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 859519 + ... + 859540.

It is an arithmetic number, because the mean of its divisors is an integer number (5157180).

Almost surely, 2^18909649 is an apocalyptic number.

It is an amenable number.

18909649 is a deficient number, since it is larger than the sum of its proper divisors (1719071).

18909649 is a wasteful number, since it uses less digits than its factorization.

18909649 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1719070.

The product of its (nonzero) digits is 139968, while the sum is 46.

The square root of 18909649 is about 4348.5226226846. The cubic root of 18909649 is about 266.4165228940.

The spelling of 18909649 in words is "eighteen million, nine hundred nine thousand, six hundred forty-nine".