6640542 has 40 divisors (see below), whose sum is σ = 15028200. Its totient is φ = 2191536.

The previous prime is 6640511. The next prime is 6640547. The reversal of 6640542 is 2450466.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (6640547) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 28884 + ... + 29112.

It is an arithmetic number, because the mean of its divisors is an integer number (375705).

Almost surely, 2^6640542 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 6640542, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (7514100).

6640542 is an abundant number, since it is smaller than the sum of its proper divisors (8387658).

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

6640542 is a wasteful number, since it uses less digits than its factorization.

6640542 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 422 (or 413 counting only the distinct ones).

The product of its (nonzero) digits is 5760, while the sum is 27.

The square root of 6640542 is about 2576.9249115952. The cubic root of 6640542 is about 187.9610414218.

The spelling of 6640542 in words is "six million, six hundred forty thousand, five hundred forty-two".