18378781019 has 2 divisors, whose sum is σ = 18378781020. Its totient is φ = 18378781018.

The previous prime is 18378780989. The next prime is 18378781067. The reversal of 18378781019 is 91018787381.

It is a happy number.

It is a weak prime.

It is an emirp because it is prime and its reverse (91018787381) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 18378781019 - 2¹⁶ = 18378715483 is a prime.

It is a super-2 number, since 2×18378781019² (a number of 21 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (18378783019) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9189390509 + 9189390510.

It is an arithmetic number, because the mean of its divisors is an integer number (9189390510).

Almost surely, 2^18378781019 is an apocalyptic number.

18378781019 is a deficient number, since it is larger than the sum of its proper divisors (1).

18378781019 is an equidigital number, since it uses as much as digits as its factorization.

18378781019 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 677376, while the sum is 53.

The spelling of 18378781019 in words is "eighteen billion, three hundred seventy-eight million, seven hundred eighty-one thousand, nineteen".