18638617786 has 4 divisors (see below), whose sum is σ = 27957926682. Its totient is φ = 9319308892.

The previous prime is 18638617733. The next prime is 18638617793. The reversal of 18638617786 is 68771683681.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 68771683681 = 19 ⋅3619562299.

It can be written as a sum of positive squares in only one way, i.e., 16196380225 + 2442237561 = 127265^2 + 49419^2 .

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 4659654445 + ... + 4659654448.

Almost surely, 2^18638617786 is an apocalyptic number.

18638617786 is a deficient number, since it is larger than the sum of its proper divisors (9319308896).

18638617786 is an equidigital number, since it uses as much as digits as its factorization.

18638617786 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9319308895.

The product of its digits is 16257024, while the sum is 61.

The spelling of 18638617786 in words is "eighteen billion, six hundred thirty-eight million, six hundred seventeen thousand, seven hundred eighty-six".