18226861 has 4 divisors (see below), whose sum is σ = 18525724. Its totient is φ = 17928000.

The previous prime is 18226847. The next prime is 18226927. The reversal of 18226861 is 16862281.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 670761 + 17556100 = 819^2 + 4190^2 .

It is a cyclic number.

It is not a de Polignac number, because 18226861 - 2¹⁵ = 18194093 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18226361) 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, 149340 + ... + 149461.

It is an arithmetic number, because the mean of its divisors is an integer number (4631431).

Almost surely, 2^18226861 is an apocalyptic number.

It is an amenable number.

18226861 is a deficient number, since it is larger than the sum of its proper divisors (298863).

18226861 is an equidigital number, since it uses as much as digits as its factorization.

18226861 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 298862.

The product of its digits is 9216, while the sum is 34.

The square root of 18226861 is about 4269.2927985792. The cubic root of 18226861 is about 263.1705534956.

It can be divided in two parts, 182268 and 61, that added together give a square (182329 = 427²).

The spelling of 18226861 in words is "eighteen million, two hundred twenty-six thousand, eight hundred sixty-one".