16656781680 has 1200 divisors, whose sum is σ = 77586284160. Its totient is φ = 3265920000.

The previous prime is 16656781667. The next prime is 16656781741. The reversal of 16656781680 is 8618765661.

16656781680 is a `hidden beast` number, since 1 + 66 + 567 + 8 + 16 + 8 + 0 = 666.

It is a Harshad number since it is a multiple of its sum of digits (54).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 239 ways as a sum of consecutive naturals, for example, 66361555 + ... + 66361805.

Almost surely, 2^16656781680 is an apocalyptic number.

16656781680 is a gapful number since it is divisible by the number (10) 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 16656781680, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (38793142080).

16656781680 is an abundant number, since it is smaller than the sum of its proper divisors (60929502480).

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

16656781680 is a wasteful number, since it uses less digits than its factorization.

16656781680 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 320 (or 298 counting only the distinct ones).

The product of its (nonzero) digits is 2903040, while the sum is 54.

The spelling of 16656781680 in words is "sixteen billion, six hundred fifty-six million, seven hundred eighty-one thousand, six hundred eighty".