6640557 has 64 divisors (see below), whose sum is σ = 12441600. Its totient is φ = 3041280.

The previous prime is 6640553. The next prime is 6640567. The reversal of 6640557 is 7550466.

It is not a de Polignac number, because 6640557 - 2² = 6640553 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (33).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (6640553) 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 63 ways as a sum of consecutive naturals, for example, 74569 + ... + 74657.

It is an arithmetic number, because the mean of its divisors is an integer number (194400).

Almost surely, 2^6640557 is an apocalyptic number.

It is an amenable number.

6640557 is a deficient number, since it is larger than the sum of its proper divisors (5801043).

6640557 is a wasteful number, since it uses less digits than its factorization.

6640557 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 146.

The product of its (nonzero) digits is 25200, while the sum is 33.

The square root of 6640557 is about 2576.9278220393. The cubic root of 6640557 is about 187.9611829471.

Subtracting 6640557 from its reverse (7550466), we obtain a palindrome (909909).

It can be divided in two parts, 66 and 40557, that multiplied together give a palindrome (2676762).

The spelling of 6640557 in words is "six million, six hundred forty thousand, five hundred fifty-seven".