678845520 has 90 divisors (see below), whose sum is σ = 2282139834. Its totient is φ = 180839040.

The previous prime is 678845501. The next prime is 678845591. The reversal of 678845520 is 25548876.

678845520 is a `hidden beast` number, since 6 + 7 + 88 + 45 + 520 = 666.

It can be written as a sum of positive squares in only one way, i.e., 543076416 + 135769104 = 23304^2 + 11652^2 .

It is a tau number, because it is divible by the number of its divisors (90).

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 17 ways as a sum of consecutive naturals, for example, 698635 + ... + 699605.

Almost surely, 2^678845520 is an apocalyptic number.

678845520 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 678845520, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1141069917).

678845520 is an abundant number, since it is smaller than the sum of its proper divisors (1603294314).

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

678845520 is an equidigital number, since it uses as much as digits as its factorization.

678845520 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1961 (or 981 counting only the distinct ones).

The product of its (nonzero) digits is 537600, while the sum is 45.

The square root of 678845520 is about 26054.6640738275. The cubic root of 678845520 is about 878.8680003846.

Multiplying 678845520 by its sum of digits (45), we get a square (30548048400 = 174780²).

678845520 divided by its sum of digits (45) gives a square (15085456 = 3884²).

The spelling of 678845520 in words is "six hundred seventy-eight million, eight hundred forty-five thousand, five hundred twenty".