18781013 has 2 divisors, whose sum is σ = 18781014. Its totient is φ = 18781012.

The previous prime is 18781001. The next prime is 18781033. The reversal of 18781013 is 31018781.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 13126129 + 5654884 = 3623^2 + 2378^2 .

It is a cyclic number.

It is not a de Polignac number, because 18781013 - 2¹⁰ = 18779989 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (18781033) 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 as a sum of consecutive naturals, namely, 9390506 + 9390507.

It is an arithmetic number, because the mean of its divisors is an integer number (9390507).

Almost surely, 2^18781013 is an apocalyptic number.

It is an amenable number.

18781013 is a deficient number, since it is larger than the sum of its proper divisors (1).

18781013 is an equidigital number, since it uses as much as digits as its factorization.

18781013 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1344, while the sum is 29.

The square root of 18781013 is about 4333.7066121278. The cubic root of 18781013 is about 265.8110337478.

Adding to 18781013 its reverse (31018781), we get a palindrome (49799794).

The spelling of 18781013 in words is "eighteen million, seven hundred eighty-one thousand, thirteen".