18214681 has 4 divisors (see below), whose sum is σ = 18250164. Its totient is φ = 18179200.

The previous prime is 18214631. The next prime is 18214727. The reversal of 18214681 is 18641281.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 18641281 = 47 ⋅396623.

It can be written as a sum of positive squares in 2 ways, for example, as 6250000 + 11964681 = 2500^2 + 3459^2 .

It is a cyclic number.

It is not a de Polignac number, because 18214681 - 2²³ = 9826073 is a prime.

It is a super-2 number, since 2×18214681² = 663549207863522, which contains 22 as substring.

It is a Smith number, since the sum of its digits (31) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (18214601) 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, 16960 + ... + 18001.

It is an arithmetic number, because the mean of its divisors is an integer number (4562541).

Almost surely, 2^18214681 is an apocalyptic number.

It is an amenable number.

18214681 is a deficient number, since it is larger than the sum of its proper divisors (35483).

18214681 is an equidigital number, since it uses as much as digits as its factorization.

18214681 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 35482.

The product of its digits is 3072, while the sum is 31.

The square root of 18214681 is about 4267.8660944317. The cubic root of 18214681 is about 263.1119196729. Note that the first 3 decimals are identical.

The spelling of 18214681 in words is "eighteen million, two hundred fourteen thousand, six hundred eighty-one".