18634720163556 has 768 divisors, whose sum is σ = 55476769259520. Its totient is φ = 4755179520000.

The previous prime is 18634720163513. The next prime is 18634720163561. The reversal of 18634720163556 is 65536102743681.

It is a junction number, because it is equal to n+sod(n) for n = 18634720163496 and 18634720163505.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 255 ways as a sum of consecutive naturals, for example, 31006189656 + ... + 31006190256.

It is an arithmetic number, because the mean of its divisors is an integer number (72235376640).

Almost surely, 2^{18634720163556} is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 18634720163556, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (27738384629760).

18634720163556 is an abundant number, since it is smaller than the sum of its proper divisors (36842049095964).

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

18634720163556 is a wasteful number, since it uses less digits than its factorization.

18634720163556 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 916 (or 914 counting only the distinct ones).

The product of its (nonzero) digits is 21772800, while the sum is 57.

The spelling of 18634720163556 in words is "eighteen trillion, six hundred thirty-four billion, seven hundred twenty million, one hundred sixty-three thousand, five hundred fifty-six".