6644861 has 4 divisors (see below), whose sum is σ = 6933792. Its totient is φ = 6355932.

The previous prime is 6644843. The next prime is 6644863. The reversal of 6644861 is 1684466.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 6644861 - 2¹⁰ = 6643837 is a prime.

It is an Ulam number.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (6644863) by changing a digit.

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 3 ways as a sum of consecutive naturals, for example, 144431 + ... + 144476.

It is an arithmetic number, because the mean of its divisors is an integer number (1733448).

Almost surely, 2^6644861 is an apocalyptic number.

It is an amenable number.

6644861 is a deficient number, since it is larger than the sum of its proper divisors (288931).

6644861 is a wasteful number, since it uses less digits than its factorization.

6644861 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 288930.

The product of its digits is 27648, while the sum is 35.

The square root of 6644861 is about 2577.7627897074. The cubic root of 6644861 is about 188.0017824639.

The spelling of 6644861 in words is "six million, six hundred forty-four thousand, eight hundred sixty-one".