18368261 has 2 divisors, whose sum is σ = 18368262. Its totient is φ = 18368260.

The previous prime is 18368249. The next prime is 18368291. The reversal of 18368261 is 16286381.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 12292036 + 6076225 = 3506^2 + 2465^2 .

It is an emirp because it is prime and its reverse (16286381) is a distict prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-18368261 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (18368221) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9184130 + 9184131.

It is an arithmetic number, because the mean of its divisors is an integer number (9184131).

Almost surely, 2^18368261 is an apocalyptic number.

It is an amenable number.

18368261 is a deficient number, since it is larger than the sum of its proper divisors (1).

18368261 is an equidigital number, since it uses as much as digits as its factorization.

18368261 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 13824, while the sum is 35.

The square root of 18368261 is about 4285.8209248638. The cubic root of 18368261 is about 263.8493410742.

The spelling of 18368261 in words is "eighteen million, three hundred sixty-eight thousand, two hundred sixty-one".