6688610640 has 100 divisors (see below), whose sum is σ = 23230558164. Its totient is φ = 1783627776.

The previous prime is 6688610629. The next prime is 6688610659. The reversal of 6688610640 is 460168866.

It can be written as a sum of positive squares in 2 ways, for example, as 4624544016 + 2064066624 = 68004^2 + 45432^2 .

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 polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 509617 + ... + 522576.

Almost surely, 2^6688610640 is an apocalyptic number.

6688610640 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

6688610640 is an abundant number, since it is smaller than the sum of its proper divisors (16541947524).

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

6688610640 is a wasteful number, since it uses less digits than its factorization.

6688610640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1032218 (or 1032203 counting only the distinct ones).

The product of its (nonzero) digits is 331776, while the sum is 45.

The square root of 6688610640 is about 81783.9265381652. The cubic root of 6688610640 is about 1884.1348031257.

The spelling of 6688610640 in words is "six billion, six hundred eighty-eight million, six hundred ten thousand, six hundred forty".