6644738 has 4 divisors (see below), whose sum is σ = 9967110. Its totient is φ = 3322368.

The previous prime is 6644717. The next prime is 6644753. The reversal of 6644738 is 8374466.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 8374466 = 2 ⋅4187233.

It can be written as a sum of positive squares in only one way, i.e., 4355569 + 2289169 = 2087^2 + 1513^2 .

It is a d-powerful number, because it can be written as 6⁵ + 6⁷ + 4⁸ + 4¹¹ + 7 + 3³ + 8⁷ .

It is a Curzon number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1661183 + ... + 1661186.

Almost surely, 2^6644738 is an apocalyptic number.

6644738 is a deficient number, since it is larger than the sum of its proper divisors (3322372).

6644738 is a wasteful number, since it uses less digits than its factorization.

6644738 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3322371.

The product of its digits is 96768, while the sum is 38.

The square root of 6644738 is about 2577.7389316996. The cubic root of 6644738 is about 188.0006224515. Note that the first 3 decimals are identical.

The spelling of 6644738 in words is "six million, six hundred forty-four thousand, seven hundred thirty-eight".