6640725 has 72 divisors (see below), whose sum is σ = 13853280. Its totient is φ = 2782080.

The previous prime is 6640687. The next prime is 6640757. The reversal of 6640725 is 5270466.

It is not a de Polignac number, because 6640725 - 2⁷ = 6640597 is a prime.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 6640692 and 6640701.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 71 ways as a sum of consecutive naturals, for example, 47706 + ... + 47844.

Almost surely, 2^6640725 is an apocalyptic number.

6640725 is a gapful number since it is divisible by the number (65) formed by its first and last digit.

It is an amenable number.

6640725 is an abundant number, since it is smaller than the sum of its proper divisors (7212555).

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

6640725 is a wasteful number, since it uses less digits than its factorization.

6640725 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 179 (or 167 counting only the distinct ones).

The product of its (nonzero) digits is 10080, while the sum is 30.

The square root of 6640725 is about 2576.9604187880. The cubic root of 6640725 is about 187.9627680155.

The spelling of 6640725 in words is "six million, six hundred forty thousand, seven hundred twenty-five".