18489691 has 4 divisors (see below), whose sum is σ = 20170584. Its totient is φ = 16808800.

The previous prime is 18489673. The next prime is 18489703. The reversal of 18489691 is 19698481.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 19698481 = 11 ⋅1790771.

It is a cyclic number.

It is not a de Polignac number, because 18489691 - 2¹⁷ = 18358619 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (18489391) 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, 840430 + ... + 840451.

It is an arithmetic number, because the mean of its divisors is an integer number (5042646).

Almost surely, 2^18489691 is an apocalyptic number.

18489691 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

18489691 is a deficient number, since it is larger than the sum of its proper divisors (1680893).

18489691 is a wasteful number, since it uses less digits than its factorization.

18489691 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1680892.

The product of its digits is 124416, while the sum is 46.

The square root of 18489691 is about 4299.9640696173. The cubic root of 18489691 is about 264.4294881981.

The spelling of 18489691 in words is "eighteen million, four hundred eighty-nine thousand, six hundred ninety-one".