681665658 has 8 divisors (see below), whose sum is σ = 1363331328. Its totient is φ = 227221884.

The previous prime is 681665629. The next prime is 681665659. The reversal of 681665658 is 856566186.

It is a sphenic number, since it is the product of 3 distinct primes.

681665658 is an admirable number.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 681665658.

It is not an unprimeable number, because it can be changed into a prime (681665659) 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 3 ways as a sum of consecutive naturals, for example, 56805466 + ... + 56805477.

It is an arithmetic number, because the mean of its divisors is an integer number (170416416).

Almost surely, 2^681665658 is an apocalyptic number.

681665658 is a primitive abundant number, since it is smaller than the sum of its proper divisors, none of which is abundant.

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

681665658 is a wasteful number, since it uses less digits than its factorization.

681665658 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 113610948.

The product of its digits is 2073600, while the sum is 51.

The square root of 681665658 is about 26108.7276212381. The cubic root of 681665658 is about 880.0833504040.

The spelling of 681665658 in words is "six hundred eighty-one million, six hundred sixty-five thousand, six hundred fifty-eight".