16638785856 has 448 divisors, whose sum is σ = 63648092160. Its totient is φ = 4133099520.

The previous prime is 16638785831. The next prime is 16638785861. The reversal of 16638785856 is 65858783661.

It is a happy number.

16638785856 is a `hidden beast` number, since 16 + 6 + 38 + 7 + 8 + 585 + 6 = 666.

It is a tau number, because it is divible by the number of its divisors (448).

It is a Harshad number since it is a multiple of its sum of digits (63).

It is a junction number, because it is equal to n+sod(n) for n = 16638785793 and 16638785802.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 3057570 + ... + 3063006.

Almost surely, 2^16638785856 is an apocalyptic number.

16638785856 is a gapful number since it is divisible by the number (16) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 16638785856, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (31824046080).

16638785856 is an abundant number, since it is smaller than the sum of its proper divisors (47009306304).

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

16638785856 is a wasteful number, since it uses less digits than its factorization.

16638785856 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5499 (or 5483 counting only the distinct ones).

The product of its digits is 58060800, while the sum is 63.

The spelling of 16638785856 in words is "sixteen billion, six hundred thirty-eight million, seven hundred eighty-five thousand, eight hundred fifty-six".