18781361 has 2 divisors, whose sum is σ = 18781362. Its totient is φ = 18781360.

The previous prime is 18781333. The next prime is 18781369. The reversal of 18781361 is 16318781.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 14554225 + 4227136 = 3815^2 + 2056^2 .

It is a cyclic number.

It is not a de Polignac number, because 18781361 - 2⁶ = 18781297 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (18781369) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9390680 + 9390681.

It is an arithmetic number, because the mean of its divisors is an integer number (9390681).

Almost surely, 2^18781361 is an apocalyptic number.

It is an amenable number.

18781361 is a deficient number, since it is larger than the sum of its proper divisors (1).

18781361 is an equidigital number, since it uses as much as digits as its factorization.

18781361 is an evil number, because the sum of its binary digits is even.

The product of its digits is 8064, while the sum is 35.

The square root of 18781361 is about 4333.7467623293. The cubic root of 18781361 is about 265.8126755063.

The spelling of 18781361 in words is "eighteen million, seven hundred eighty-one thousand, three hundred sixty-one".