18698081 has 4 divisors (see below), whose sum is σ = 18708372. Its totient is φ = 18687792.

The previous prime is 18698059. The next prime is 18698087. The reversal of 18698081 is 18089681.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length, and also an emirpimes, since its reverse is a distinct semiprime: 18089681 = 859 ⋅21059.

It can be written as a sum of positive squares in 2 ways, for example, as 4326400 + 14371681 = 2080^2 + 3791^2 .

It is a cyclic number.

It is not a de Polignac number, because 18698081 - 2¹⁰ = 18697057 is a prime.

It is a super-2 number, since 2×18698081² = 699236466165122, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (18698087) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1610 + ... + 6323.

It is an arithmetic number, because the mean of its divisors is an integer number (4677093).

Almost surely, 2^18698081 is an apocalyptic number.

It is an amenable number.

18698081 is a deficient number, since it is larger than the sum of its proper divisors (10291).

18698081 is an equidigital number, since it uses as much as digits as its factorization.

18698081 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10290.

The product of its (nonzero) digits is 27648, while the sum is 41.

The square root of 18698081 is about 4324.1277733203. The cubic root of 18698081 is about 265.4192059717.

Subtracting from 18698081 its reverse (18089681), we obtain a square (608400 = 780²).

The spelling of 18698081 in words is "eighteen million, six hundred ninety-eight thousand, eighty-one".