18219809471 has 4 divisors (see below), whose sum is σ = 18712236792. Its totient is φ = 17727382152.

The previous prime is 18219809407. The next prime is 18219809501. The reversal of 18219809471 is 17490891281.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 17490891281 = 47 ⋅372146623.

It is a cyclic number.

It is not a de Polignac number, because 18219809471 - 2⁶ = 18219809407 is a prime.

It is a super-3 number, since 3×18219809471³ (a number of 32 digits) contains 333 as substring. Note that it is a super-d number also for d = 2.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18219806471) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 246213605 + ... + 246213678.

It is an arithmetic number, because the mean of its divisors is an integer number (4678059198).

Almost surely, 2^18219809471 is an apocalyptic number.

18219809471 is a deficient number, since it is larger than the sum of its proper divisors (492427321).

18219809471 is an equidigital number, since it uses as much as digits as its factorization.

18219809471 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 492427320.

The product of its (nonzero) digits is 290304, while the sum is 50.

The spelling of 18219809471 in words is "eighteen billion, two hundred nineteen million, eight hundred nine thousand, four hundred seventy-one".