6639930 has 96 divisors (see below), whose sum is σ = 19880640. Its totient is φ = 1520640.

The previous prime is 6639929. The next prime is 6639937. The reversal of 6639930 is 399366.

It is a Smith number, since the sum of its digits (36) coincides with the sum of the digits of its prime factors.

It is a d-powerful number, because it can be written as 6² + 6⁸ + 3¹¹ + 9² + 9² + 3¹⁴ + 0 .

It is not an unprimeable number, because it can be changed into a prime (6639937) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 18634 + ... + 18986.

It is an arithmetic number, because the mean of its divisors is an integer number (207090).

Almost surely, 2^6639930 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 6639930, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (9940320).

6639930 is an abundant number, since it is smaller than the sum of its proper divisors (13240710).

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

6639930 is a wasteful number, since it uses less digits than its factorization.

6639930 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 396 (or 393 counting only the distinct ones).

The product of its (nonzero) digits is 26244, while the sum is 36.

The square root of 6639930 is about 2576.8061626750. The cubic root of 6639930 is about 187.9552670090.

It can be divided in two parts, 6639 and 930, that added together give a square (7569 = 87²).

The spelling of 6639930 in words is "six million, six hundred thirty-nine thousand, nine hundred thirty".