66778561080 has 320 divisors, whose sum is σ = 279835015680. Its totient is φ = 13876012800.

The previous prime is 66778561043. The next prime is 66778561097. The reversal of 66778561080 is 8016587766.

66778561080 is a `hidden beast` number, since 6 + 6 + 7 + 78 + 561 + 0 + 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 79 ways as a sum of consecutive naturals, for example, 115645 + ... + 383315.

It is an arithmetic number, because the mean of its divisors is an integer number (874484424).

Almost surely, 2^66778561080 is an apocalyptic number.

66778561080 is a gapful number since it is divisible by the number (60) 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 66778561080, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (139917507840).

66778561080 is an abundant number, since it is smaller than the sum of its proper divisors (213056454600).

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

66778561080 is a wasteful number, since it uses less digits than its factorization.

66778561080 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 267712 (or 267699 counting only the distinct ones).

The product of its (nonzero) digits is 3386880, while the sum is 54.

The spelling of 66778561080 in words is "sixty-six billion, seven hundred seventy-eight million, five hundred sixty-one thousand, eighty".