18188897 has 2 divisors, whose sum is σ = 18188898. Its totient is φ = 18188896.

The previous prime is 18188893. The next prime is 18188903. The reversal of 18188897 is 79888181.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 13845841 + 4343056 = 3721^2 + 2084^2 .

It is an emirp because it is prime and its reverse (79888181) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 18188897 - 2² = 18188893 is a prime.

It is a super-3 number, since 3×18188897³ (a number of 23 digits) contains 333 as substring.

It is not a weakly prime, because it can be changed into another prime (18188893) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9094448 + 9094449.

It is an arithmetic number, because the mean of its divisors is an integer number (9094449).

Almost surely, 2^18188897 is an apocalyptic number.

It is an amenable number.

18188897 is a deficient number, since it is larger than the sum of its proper divisors (1).

18188897 is an equidigital number, since it uses as much as digits as its factorization.

18188897 is an evil number, because the sum of its binary digits is even.

The product of its digits is 258048, while the sum is 50.

The square root of 18188897 is about 4264.8443113436. The cubic root of 18188897 is about 262.9877106837.

The spelling of 18188897 in words is "eighteen million, one hundred eighty-eight thousand, eight hundred ninety-seven".