18219771 has 6 divisors (see below), whose sum is σ = 26317460. Its totient is φ = 12146508.

The previous prime is 18219763. The next prime is 18219787. The reversal of 18219771 is 17791281.

It is not a de Polignac number, because 18219771 - 2³ = 18219763 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (18219791) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 1012201 + ... + 1012218.

Almost surely, 2^18219771 is an apocalyptic number.

18219771 is a deficient number, since it is larger than the sum of its proper divisors (8097689).

18219771 is a wasteful number, since it uses less digits than its factorization.

18219771 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2024425 (or 2024422 counting only the distinct ones).

The product of its digits is 7056, while the sum is 36.

The square root of 18219771 is about 4268.4623695190. The cubic root of 18219771 is about 263.1364258198.

The spelling of 18219771 in words is "eighteen million, two hundred nineteen thousand, seven hundred seventy-one".