18581135816 has 8 divisors (see below), whose sum is σ = 34839629670. Its totient is φ = 9290567904.

The previous prime is 18581135803. The next prime is 18581135851. The reversal of 18581135816 is 61853118581.

It is a happy number.

It can be written as a sum of positive squares in only one way, i.e., 18531376900 + 49758916 = 136130^2 + 7054^2 .

It is a tau number, because it is divible by the number of its divisors (8).

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1161320981 + ... + 1161320996.

Almost surely, 2^18581135816 is an apocalyptic number.

It is an amenable number.

18581135816 is a deficient number, since it is larger than the sum of its proper divisors (16258493854).

18581135816 is a wasteful number, since it uses less digits than its factorization.

18581135816 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2322641983 (or 2322641979 counting only the distinct ones).

The product of its digits is 230400, while the sum is 47.

The spelling of 18581135816 in words is "eighteen billion, five hundred eighty-one million, one hundred thirty-five thousand, eight hundred sixteen".