18247681 has 4 divisors (see below), whose sum is σ = 19321092. Its totient is φ = 17174272.

The previous prime is 18247679. The next prime is 18247709. The reversal of 18247681 is 18674281.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 18674281 = 1361 ⋅13721.

It can be written as a sum of positive squares in 2 ways, for example, as 9247681 + 9000000 = 3041^2 + 3000^2 .

It is a cyclic number.

It is not a de Polignac number, because 18247681 - 2¹ = 18247679 is a prime.

It is a super-2 number, since 2×18247681² = 665955723755522, which contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 18247681.

It is not an unprimeable number, because it can be changed into a prime (18247661) 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, 536680 + ... + 536713.

It is an arithmetic number, because the mean of its divisors is an integer number (4830273).

Almost surely, 2^18247681 is an apocalyptic number.

It is an amenable number.

18247681 is a deficient number, since it is larger than the sum of its proper divisors (1073411).

18247681 is a wasteful number, since it uses less digits than its factorization.

18247681 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1073410.

The product of its digits is 21504, while the sum is 37.

The square root of 18247681 is about 4271.7304456157. The cubic root of 18247681 is about 263.2707193260.

The spelling of 18247681 in words is "eighteen million, two hundred forty-seven thousand, six hundred eighty-one".