685694880 has 144 divisors (see below), whose sum is σ = 2519997480. Its totient is φ = 168781824.

The previous prime is 685694869. The next prime is 685694917. The reversal of 685694880 is 88496586.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 588159504 + 97535376 = 24252^2 + 9876^2 .

It is a tau number, because it is divible by the number of its divisors (144).

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 406 + ... + 37034.

Almost surely, 2^685694880 is an apocalyptic number.

685694880 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 685694880, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1259998740).

685694880 is an abundant number, since it is smaller than the sum of its proper divisors (1834302600).

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

685694880 is a wasteful number, since it uses less digits than its factorization.

685694880 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 36663 (or 36652 counting only the distinct ones).

The product of its (nonzero) digits is 3317760, while the sum is 54.

The square root of 685694880 is about 26185.7762917199. The cubic root of 685694880 is about 881.8139580148.

The spelling of 685694880 in words is "six hundred eighty-five million, six hundred ninety-four thousand, eight hundred eighty".