6640644 has 24 divisors (see below), whose sum is σ = 15537088. Its totient is φ = 2207520.

The previous prime is 6640639. The next prime is 6640651. The reversal of 6640644 is 4460466.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 7134 + ... + 8010.

Almost surely, 2^6640644 is an apocalyptic number.

It is an amenable number.

6640644 is an abundant number, since it is smaller than the sum of its proper divisors (8896444).

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

6640644 is a wasteful number, since it uses less digits than its factorization.

6640644 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1515 (or 1513 counting only the distinct ones).

The product of its (nonzero) digits is 13824, while the sum is 30.

The square root of 6640644 is about 2576.9447025499. The cubic root of 6640644 is about 187.9620037894.

The spelling of 6640644 in words is "six million, six hundred forty thousand, six hundred forty-four".