6406660 has 48 divisors (see below), whose sum is σ = 14866992. Its totient is φ = 2304000.

The previous prime is 6406657. The next prime is 6406679. The reversal of 6406660 is 666046.

It can be written as a sum of positive squares in 8 ways, for example, as 799236 + 5607424 = 894^2 + 2368^2 .

It is an Ulam number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 10360 + ... + 10960.

It is an arithmetic number, because the mean of its divisors is an integer number (309729).

Almost surely, 2^6406660 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 6406660, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (7433496).

6406660 is an abundant number, since it is smaller than the sum of its proper divisors (8460332).

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

6406660 is a wasteful number, since it uses less digits than its factorization.

6406660 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 664 (or 662 counting only the distinct ones).

The product of its (nonzero) digits is 5184, while the sum is 28.

The square root of 6406660 is about 2531.1380839456. The cubic root of 6406660 is about 185.7279330630.

The spelling of 6406660 in words is "six million, four hundred six thousand, six hundred sixty".