18691319508 has 12 divisors (see below), whose sum is σ = 43613078880. Its totient is φ = 6230439832.

The previous prime is 18691319467. The next prime is 18691319509. The reversal of 18691319508 is 80591319681.

It is a tau number, because it is divible by the number of its divisors (12).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18691319509) 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, 778804968 + ... + 778804991.

It is an arithmetic number, because the mean of its divisors is an integer number (3634423240).

Almost surely, 2^18691319508 is an apocalyptic number.

It is an amenable number.

18691319508 is an abundant number, since it is smaller than the sum of its proper divisors (24921759372).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

18691319508 is a wasteful number, since it uses less digits than its factorization.

18691319508 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1557609966 (or 1557609964 counting only the distinct ones).

The product of its (nonzero) digits is 466560, while the sum is 51.

The spelling of 18691319508 in words is "eighteen billion, six hundred ninety-one million, three hundred nineteen thousand, five hundred eight".