18630694081 has 4 divisors (see below), whose sum is σ = 18652434372. Its totient is φ = 18608953792.

The previous prime is 18630694079. The next prime is 18630694099. The reversal of 18630694081 is 18049603681.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 18049603681 = 17 ⋅1061741393.

It can be written as a sum of positive squares in 2 ways, for example, as 9252708481 + 9377985600 = 96191^2 + 96840^2 .

It is a cyclic number.

It is not a de Polignac number, because 18630694081 - 2¹ = 18630694079 is a prime.

It is a super-2 number, since 2×18630694081² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (18630694001) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 10868860 + ... + 10870573.

It is an arithmetic number, because the mean of its divisors is an integer number (4663108593).

Almost surely, 2^18630694081 is an apocalyptic number.

It is an amenable number.

18630694081 is a deficient number, since it is larger than the sum of its proper divisors (21740291).

18630694081 is an equidigital number, since it uses as much as digits as its factorization.

18630694081 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 21740290.

The product of its (nonzero) digits is 248832, while the sum is 46.

The spelling of 18630694081 in words is "eighteen billion, six hundred thirty million, six hundred ninety-four thousand, eighty-one".