6640740 has 72 divisors (see below), whose sum is σ = 20442240. Its totient is φ = 1744704.

The previous prime is 6640687. The next prime is 6640757. The reversal of 6640740 is 470466.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 13987 + ... + 14453.

It is an arithmetic number, because the mean of its divisors is an integer number (283920).

Almost surely, 2^6640740 is an apocalyptic number.

6640740 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 6640740, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (10221120).

6640740 is an abundant number, since it is smaller than the sum of its proper divisors (13801500).

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

6640740 is a wasteful number, since it uses less digits than its factorization.

6640740 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 561 (or 556 counting only the distinct ones).

The product of its (nonzero) digits is 4032, while the sum is 27.

The square root of 6640740 is about 2576.9633291919. The cubic root of 6640740 is about 187.9629095382.

The spelling of 6640740 in words is "six million, six hundred forty thousand, seven hundred forty".