18720819688 has 8 divisors (see below), whose sum is σ = 35101536930. Its totient is φ = 9360409840.

The previous prime is 18720819671. The next prime is 18720819697. The reversal of 18720819688 is 88691802781.

It can be written as a sum of positive squares in only one way, i.e., 15154102404 + 3566717284 = 123102^2 + 59722^2 .

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

It is an unprimeable number.

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

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1170051223 + ... + 1170051238.

Almost surely, 2^18720819688 is an apocalyptic number.

It is an amenable number.

18720819688 is a deficient number, since it is larger than the sum of its proper divisors (16380717242).

18720819688 is a wasteful number, since it uses less digits than its factorization.

18720819688 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2340102467 (or 2340102463 counting only the distinct ones).

The product of its (nonzero) digits is 3096576, while the sum is 58.

The spelling of 18720819688 in words is "eighteen billion, seven hundred twenty million, eight hundred nineteen thousand, six hundred eighty-eight".