657781621968 has 40 divisors (see below), whose sum is σ = 1700997968448. Its totient is φ = 219037472512.

The previous prime is 657781621961. The next prime is 657781621993. The reversal of 657781621968 is 869126187756.

It is a happy number.

It is a junction number, because it is equal to n+sod(n) for n = 657781621899 and 657781621908.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (657781621961) by changing a digit.

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 7 ways as a sum of consecutive naturals, for example, 6923205 + ... + 7017572.

Almost surely, 2^657781621968 is an apocalyptic number.

It is an amenable number.

657781621968 is an abundant number, since it is smaller than the sum of its proper divisors (1043216346480).

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

657781621968 is a wasteful number, since it uses less digits than its factorization.

657781621968 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 13941771 (or 13941765 counting only the distinct ones).

The product of its digits is 60963840, while the sum is 66.

The spelling of 657781621968 in words is "six hundred fifty-seven billion, seven hundred eighty-one million, six hundred twenty-one thousand, nine hundred sixty-eight".