18348235981 has 2 divisors, whose sum is σ = 18348235982. Its totient is φ = 18348235980.

The previous prime is 18348235967. The next prime is 18348236021. The reversal of 18348235981 is 18953284381.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 13973604100 + 4374631881 = 118210^2 + 66141^2 .

It is a cyclic number.

It is not a de Polignac number, because 18348235981 - 2¹⁹ = 18347711693 is a prime.

It is a super-2 number, since 2×18348235981² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (18348235921) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9174117990 + 9174117991.

It is an arithmetic number, because the mean of its divisors is an integer number (9174117991).

Almost surely, 2^18348235981 is an apocalyptic number.

It is an amenable number.

18348235981 is a deficient number, since it is larger than the sum of its proper divisors (1).

18348235981 is an equidigital number, since it uses as much as digits as its factorization.

18348235981 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1658880, while the sum is 52.

The spelling of 18348235981 in words is "eighteen billion, three hundred forty-eight million, two hundred thirty-five thousand, nine hundred eighty-one".