18786397 has 4 divisors (see below), whose sum is σ = 21470176. Its totient is φ = 16102620.

The previous prime is 18786379. The next prime is 18786409. The reversal of 18786397 is 79368781.

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: 79368781 = 5393 ⋅14717.

It is a cyclic number.

It is not a de Polignac number, because 18786397 - 2¹⁵ = 18753629 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 18786397.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18786337) 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, 1341879 + ... + 1341892.

It is an arithmetic number, because the mean of its divisors is an integer number (5367544).

Almost surely, 2^18786397 is an apocalyptic number.

It is an amenable number.

18786397 is a deficient number, since it is larger than the sum of its proper divisors (2683779).

18786397 is an equidigital number, since it uses as much as digits as its factorization.

18786397 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2683778.

The product of its digits is 508032, while the sum is 49.

The square root of 18786397 is about 4334.3277448758. The cubic root of 18786397 is about 265.8364315591.

The spelling of 18786397 in words is "eighteen million, seven hundred eighty-six thousand, three hundred ninety-seven".