678208661 has 12 divisors (see below), whose sum is σ = 739700640. Its totient is φ = 621513360.

The previous prime is 678208621. The next prime is 678208673. The reversal of 678208661 is 166802876.

It is not a de Polignac number, because 678208661 - 2¹⁰ = 678207637 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (678208621) by changing a digit.

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 11 ways as a sum of consecutive naturals, for example, 9056 + ... + 37926.

It is an arithmetic number, because the mean of its divisors is an integer number (61641720).

Almost surely, 2^678208661 is an apocalyptic number.

It is an amenable number.

678208661 is a deficient number, since it is larger than the sum of its proper divisors (61491979).

678208661 is a wasteful number, since it uses less digits than its factorization.

678208661 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 29036 (or 29023 counting only the distinct ones).

The product of its (nonzero) digits is 193536, while the sum is 44.

The square root of 678208661 is about 26042.4396130624. The cubic root of 678208661 is about 878.5930776897.

The spelling of 678208661 in words is "six hundred seventy-eight million, two hundred eight thousand, six hundred sixty-one".