6643725 has 24 divisors (see below), whose sum is σ = 11984352. Its totient is φ = 3220800.

The previous prime is 6643723. The next prime is 6643729. The reversal of 6643725 is 5273466.

It is not a de Polignac number, because 6643725 - 2¹ = 6643723 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (33).

It is an Ulam number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (6643723) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 3202 + ... + 4851.

It is an arithmetic number, because the mean of its divisors is an integer number (499348).

Almost surely, 2^6643725 is an apocalyptic number.

It is an amenable number.

6643725 is a deficient number, since it is larger than the sum of its proper divisors (5340627).

6643725 is a wasteful number, since it uses less digits than its factorization.

6643725 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8077 (or 8072 counting only the distinct ones).

The product of its digits is 30240, while the sum is 33.

The square root of 6643725 is about 2577.5424341803. The cubic root of 6643725 is about 187.9910683096.

The spelling of 6643725 in words is "six million, six hundred forty-three thousand, seven hundred twenty-five".