18438681011 has 2 divisors, whose sum is σ = 18438681012. Its totient is φ = 18438681010.

The previous prime is 18438680993. The next prime is 18438681017. The reversal of 18438681011 is 11018683481.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-18438681011 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 18438681011.

It is not a weakly prime, because it can be changed into another prime (18438681017) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9219340505 + 9219340506.

It is an arithmetic number, because the mean of its divisors is an integer number (9219340506).

Almost surely, 2^18438681011 is an apocalyptic number.

18438681011 is a deficient number, since it is larger than the sum of its proper divisors (1).

18438681011 is an equidigital number, since it uses as much as digits as its factorization.

18438681011 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 36864, while the sum is 41.

The spelling of 18438681011 in words is "eighteen billion, four hundred thirty-eight million, six hundred eighty-one thousand, eleven".