6645744 has 120 divisors (see below), whose sum is σ = 22439040. Its totient is φ = 1793664.

The previous prime is 6645739. The next prime is 6645757. The reversal of 6645744 is 4475466.

6645744 is a `hidden beast` number, since 6 + 645 + 7 + 4 + 4 = 666.

It is a hoax number, since the sum of its digits (36) coincides with the sum of the digits of its distinct prime factors.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a junction number, because it is equal to n+sod(n) for n = 6645699 and 6645708.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 18979 + ... + 19325.

It is an arithmetic number, because the mean of its divisors is an integer number (186992).

Almost surely, 2^6645744 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 6645744, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (11219520).

6645744 is an abundant number, since it is smaller than the sum of its proper divisors (15793296).

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

6645744 is a wasteful number, since it uses less digits than its factorization.

6645744 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 387 (or 378 counting only the distinct ones).

The product of its digits is 80640, while the sum is 36.

The square root of 6645744 is about 2577.9340565655. The cubic root of 6645744 is about 188.0101096118.

The spelling of 6645744 in words is "six million, six hundred forty-five thousand, seven hundred forty-four".