18181797 has 4 divisors (see below), whose sum is σ = 24242400. Its totient is φ = 12121196.

The previous prime is 18181783. The next prime is 18181817. The reversal of 18181797 is 79718181.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 79718181 = 3 ⋅26572727.

It is a cyclic number.

It is not a de Polignac number, because 18181797 - 2¹⁶ = 18116261 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18180797) 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, 3030297 + ... + 3030302.

It is an arithmetic number, because the mean of its divisors is an integer number (6060600).

Almost surely, 2^18181797 is an apocalyptic number.

It is an amenable number.

18181797 is a deficient number, since it is larger than the sum of its proper divisors (6060603).

18181797 is an equidigital number, since it uses as much as digits as its factorization.

18181797 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6060602.

The product of its digits is 28224, while the sum is 42.

The square root of 18181797 is about 4264.0118433231. The cubic root of 18181797 is about 262.9534873192.

The spelling of 18181797 in words is "eighteen million, one hundred eighty-one thousand, seven hundred ninety-seven".