6646725687 has 64 divisors (see below), whose sum is σ = 10560128000. Its totient is φ = 3716254080.

The previous prime is 6646725661. The next prime is 6646725689. The reversal of 6646725687 is 7865276466.

It is not a de Polignac number, because 6646725687 - 2²⁷ = 6512507959 is a prime.

It is a Smith number, since the sum of its digits (57) coincides with the sum of the digits of its prime factors.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (6646725689) by changing a digit.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 15787737 + ... + 15788157.

It is an arithmetic number, because the mean of its divisors is an integer number (165002000).

Almost surely, 2^6646725687 is an apocalyptic number.

6646725687 is a gapful number since it is divisible by the number (67) formed by its first and last digit.

6646725687 is a deficient number, since it is larger than the sum of its proper divisors (3913402313).

6646725687 is a wasteful number, since it uses less digits than its factorization.

6646725687 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 741 (or 727 counting only the distinct ones).

The product of its digits is 20321280, while the sum is 57.

The square root of 6646725687 is about 81527.4535785339. The cubic root of 6646725687 is about 1880.1936656346.

The spelling of 6646725687 in words is "six billion, six hundred forty-six million, seven hundred twenty-five thousand, six hundred eighty-seven".