18219689 has 4 divisors (see below), whose sum is σ = 19178640. Its totient is φ = 17260740.

The previous prime is 18219683. The next prime is 18219697. The reversal of 18219689 is 98691281.

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: 98691281 = 13 ⋅7591637.

It is not a de Polignac number, because 18219689 - 2⁴ = 18219673 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (18219683) 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, 479447 + ... + 479484.

It is an arithmetic number, because the mean of its divisors is an integer number (4794660).

Almost surely, 2^18219689 is an apocalyptic number.

18219689 is a gapful number since it is divisible by the number (19) formed by its first and last digit.

It is an amenable number.

18219689 is a deficient number, since it is larger than the sum of its proper divisors (958951).

18219689 is an equidigital number, since it uses as much as digits as its factorization.

18219689 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 958950.

The product of its digits is 62208, while the sum is 44.

The square root of 18219689 is about 4268.4527641758. The cubic root of 18219689 is about 263.1360310615.

The spelling of 18219689 in words is "eighteen million, two hundred nineteen thousand, six hundred eighty-nine".