6644645 has 24 divisors (see below), whose sum is σ = 9539064. Its totient is φ = 4427136.

The previous prime is 6644621. The next prime is 6644647. The reversal of 6644645 is 5464466.

It can be written as a sum of positive squares in 4 ways, for example, as 3869089 + 2775556 = 1967^2 + 1666^2 .

It is not a de Polignac number, because 6644645 - 2⁶ = 6644581 is a prime.

It is a hoax number, since the sum of its digits (35) 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 (35).

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (6644647) 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, 8699 + ... + 9431.

It is an arithmetic number, because the mean of its divisors is an integer number (397461).

Almost surely, 2^6644645 is an apocalyptic number.

It is an amenable number.

6644645 is a deficient number, since it is larger than the sum of its proper divisors (2894419).

6644645 is a wasteful number, since it uses less digits than its factorization.

6644645 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 789 (or 782 counting only the distinct ones).

The product of its digits is 69120, while the sum is 35.

The square root of 6644645 is about 2577.7208925716. The cubic root of 6644645 is about 187.9997453595. Note that the first 3 decimals are identical.

The spelling of 6644645 in words is "six million, six hundred forty-four thousand, six hundred forty-five".